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TN 8th Tamil இயல் 2-ஈடில்லா இயற்கை - திருக்குறள் Important Questions And Answers Study Material - QB365 Set A

Published on: 09/12/2019
Term 2 Geometry
Download Tamil Nadu 8th Standard Maths question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Maths Test1.
Construct a parallelogram DUCK with DC = 8 cm, UK = 6 cm and ㄥDOU = 1100. Also find its area.
2.
Δ ABC is equilateral and CD of the right triangle BCD is 8 cm. Find the side of the equilateral Δ ABC and also BD.
3.
Find the area of a rectangular plot of land shown in the figure.
4.
A 20- feet ladder leans against a wall at height of 16 feet from the ground. How far is the base of the ladder from the wall?
5.
Can a right triangle have sides that measure 5cm, 12cm and 13cm?
6.
Mayan travelled 28 km due north and then 21 km due east. What is the least distance that he could have travelled from his starting point?
7.
Rithika buys an LED TV which has a 25 inches screen. If its height is 7 inches, how wide is the screen? Her TV cabinet is 20 inches wide. Will the TV fit into the cabinet? Why?
8.
The sides of a triangle are 1.2 cm, 3.5 cm and 3.7 cm. Is this triangle a right triangle? If so, which side is the hypotenuse?
9.
Find the distance between the helicopter and the ship.

10.
An isosceles triangle has equal sides each 13 cm and a base 24 cm in length. Find its height.
11.
The sides of a right angled triangle are in the ratio 5: 12: 13 and its perimeter is 120 units then, the sides are ______________.
25, 36, 59
10, 24, 26
36, 39, 45
20, 48, 52
12.
If the square of the hypotenuse of an isosceles right triangle is 50 cm2, the length of each side is ____________.
25 cm
5 cm
10 cm
20 cm
13.
The area of a rectangle of length 21 cm and diagonal 29 cm is __________cm2.
609
580
420
210
14.
The hypotenuse of a right angled triangle of sides 12cm and 16cm is __________.
28 cm
20 cm
24 cm
21 cm
15.
If Δ GUT is isosceles and right angled, then ㄥTUG is ________.

300
400
450
550
16.
Construct a trapezium DESK in which \(\overset { \_ \_ }{ DE } \) is parallel to \(\overset { \_ \_ }{ KS } \), DE = 8 cm, ES = 5.5 cm, KS = 5 cm and KD = 6 cm. Find also its area.
17.
Construct a trapezium DEAN in which \(\overset { \_ \_ }{ DE } \) is parallel to \(\overset { \_ \_ }{ NA } \), DE = 7 cm, EA = 6.5 cm ㄥEDN = 1000 and ㄥDEA = 700. Also find its area.
18.
Construct a trapezium CARD in which \(\overset { \_ }{ CA } \) is parallel to \(\overset { \_ }{ DR} \), CA = 9 cm, ㄥCAR = 70, AR = 6 cm and CD = 7 cm. Also find its area.
19.
Construct a trapezium BOAT in which \(\overset { - }{ BO } \) is parallel to \(\overset { - }{ TA } \), BO = 7 cm, OA = 6 cm, BA = 10 cm and TA = 6 cm. Also find its area.
1.
Given:
DC = 8 cm, UK = 6 cm and ㄥDOU = 1100
.png)

Steps:
1. Draw a line segment DC = 8 cm.
2. Mark O the midpoint of \(\overset { \_ \_ }{ DC } \).
3. Draw a line \(\overset { \_ \_ }{ XY } \) through O which makes ㄥDOY = 1100.
4. With O as centre and 3 cm as radius draw two arcs on \(\overset { \_ \_ }{XY } \)on either sides of \(\overset { \_ \_ }{DC } \). Let the arcs cut \(\overset { \_ \_ }{ OX } \)at K and \(\overset { \_ \_ }{OY } \) at U
5. Join \(\overset { \_ \_ }{DU } \) , \(\overset { \_ \_ }{UC } \), \(\overset { \_ \_ }{CK } \) and \(\overset { \_ \_ }{KD } \).
6. DUCK is the required parallelogram.
Calculation of Area:
Area of the parallelogram DUCK = bh sq.units
= 5.8 x 3.9 = 22.62sq.cm
2.
As Δ ABC is equilateral from the figure, AB = BC = AC = (x − 2) cm.
∴ From Δ BCD, by Pythagoras theorem
BD2 = BC2 + CD2
⇒ (x + 2)2 = (x − 2)2 + 82
x2 + 4x + 4 = x2 − 4x + 4 + 82
⇒ 8x = 82
⇒ x = 8 cm
∴ The side of the equilateral Δ ABC = 6 cm and BD = 10 cm.

3.
Here, the hypotenuse is 29 m. One side of the right triangle is 20 m. let the other side be ‘l’ m Therefore, by Pythagoras theorem,
l2 = 292 − 202 = 841 − 400 = 441 = 212
∴ l = 21m
Therefore, the area rectangular plot of land = l × b square units. = 20 × 21 = 210 m2.
4.
The ladder, wall and the ground form a right triangle with the ladder as the hypotenuse. From the figure, by Pythagoras theorem,
202 = 162 + x2
⇒ 400 = 256 + x2
⇒ x2 = 400 − 256 = 144 = 122
⇒ x = 12 feet
Therefore, the base (foot) of the ladder is 12 feet away from the wall.

5.
Take a = 5, b = 12 and c = 13
Now, a2 + b2 = 52 +122 = 25 +144 = 169 = 132 = c2
By the converse of Pythagoras theorem, the triangle with given measures is a right angled triangle.
6.
From the figure AC is to be found.
By using Pythagoras theorem,
AC2 = AB2 + BC2 = 282 + 212 = 784 + 441 = 1225 = 352
∴ AC = 35 km
7.

Let x be the wide of the screen.
From the figure,
x2 + 22 = 252
x2 + 49 = 625
x2 = 625 - 49
= 576
\(x=\sqrt{576}\)
= 24
The wide of the screen is 24 inches
The TV cabinet wide is 21 inches. It is not fit for the TV which has the wide screen 24 inches
8.
Yes, the side of length 3.7 cm is the hypotenuse.
9.
From the figure
d2 = 802 + 1502
= 6400 + 22500
d2 = 28900
d = 170
The distance between the helicopter and the ship is 170 m.
10.

Let \(\triangle\) ABC is a isosceles triangle.
Draw AD perpendicular to BC, we get two right angled triangles.
In \(\triangle\)ABD
132 = x2 + h2 ..........(1)
In \(\triangle\) ADC,
132 = h2 +(24 - x)2 .........(2)
From (1) and (2)
\(
x^{2}+\mathrm{h}^{2} =(24-x)^{2}+\mathrm{h}^{2}
\)
\(x^{2} =(24-x)^{2} \\
x^{2} =576-48 x+x^{2}
\)
\(0 = 576-48 x \\
\therefore \ 48 x =576
\)
\(x =\frac{576}{48} \\
x =12
\)
Put x = 12 in (1), we get 132 = x2 +h2
\(
13^{2} =12^{2}+h^{2}
\)
\(169 =144+h^{2}
\)
\(\therefore h^{2} =169-144
\)
\(h^{2} =25
\)
\(h =\sqrt{25}\)
= 5
Height of the isosceles triangle is 5 cm.
11.
(d)
20, 48, 52
12.
(b)
5 cm
13.
(c)
420
14.
(b)
20 cm
15.
(c)
450
16.
Given:
DE = 8 cm, ES = 5.5 cm, KS = 5 cm, KD = 6 cm and \(\overset { \_ \_ }{ DE } \) || \(\overset { \_ \_ }{ KS } \)
.png)

Steps:
1. Draw a line segment DE = 8cm.
2. Mark the point A on DE such that DA = 5 cm.
3. With A and E as centres, draw arcs of radii 6 cm and 5.5 cm respectively. Let them cut at S. Join AS and ES.
4. With D and S as centres, draw arcs of radii 6 cm and 5 cm respectively. Let them cut at K. Join DK and KS.
5. DESK is the required trapezium.
Calculation of area:
Area of the trapezium DESK = \(\frac { 1 }{ 2 } \) x h x (a + b) sq. units
= \(\frac { 1 }{ 2 } \) x 5.5 x (8 + 5) = 35.75 sq. cm
17.
Given:
DE = 7 cm, EA = 6.5 cm ㄥEDN = 1000 and ㄥDEA = 700 and \(\overset { \_ \_ }{ DE } \) || \(\overset { \_ \_ }{ NA} \)
.png)

Steps:
1. Draw a line segment DE = 7cm.
2. Construct an angle ㄥDEX = 700 at E.
3. With E as centre draw an arc of radius 6.5cm cutting EX at A.
4. Draw AY parallel to DE.
5. Construct an angle ㄥEDZ = 1000 at D cutting AY at N.
6. DEAN is the required trapezium.
Calculation of area:
Area of the trapezium DEAN = \(\frac { 1 }{ 2 } \) x h x (a+b) sq. units
= \(\frac { 1 }{ 2 } \) x 6.1 x (7 + 5.8) = 39.04 sq. units
18.
Given:
CA = 9 cm, ㄥCAR = 700 AR = 6 cm, and CD = 7 cm and \(\overset { \_ }{ CA } \) || \(\overset { \_ }{ DR } \)
.png)

Steps:
1. Draw a line segment CA = 9 cm.
2. Construct an angle ㄥCAX = 700 at A.
3. With A as centre, draw an arc of radius 6 cm cutting AX at R.
4. Draw RY parallel to CA.
5. With C as centre, draw an arc of radius 7 cm cutting RY at D.
6. Join CD. CARD is the required trapezium.
Calculation of area:
Area of the trapezium CARD = \(\frac { 1 }{ 2 } \) x h x(a + b) sq.units
= \(\frac { 1 }{ 2 } \) x 5.6 x (9 + 11) = 56 sq. cm
19.
Given:
BO = 7cm, OA = 6cm, BA = 10cm,
TA = 6 cm and \(\overset { - }{ BO } \) || \(\overset { - }{ TA } \)
.png)

Steps:
1. Draw a line segment BO = 7 cm.
2. With B and O as centres, draw arcs of radii 10cm and 6cm respectively and let them cut at A.
3. Join BA and OA.
4. Draw AX parallel to BO
5. With A as centre, draw an arc of radius 6cm cutting AX at T.
6. Join BT. BOAT is the required trapezium.
Calculation of area:
Area of the trapezium BOAT = \(\frac { 1 }{ 2 } \) x h x (a+b) sq units
= \(\frac { 1 }{ 2 } \) x 5.9 x (7+6) = 38.35 sq. cm
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