Since it is given that the polygon is a regular polygon, all sides will be equal.
Therefore, the number of sides of a polygon = \(\cfrac { perimeter }{ oneside } \) 
= \(\cfrac { 17.5 }{ 2.5 } =\cfrac { 175 }{ 25 } =7\) (Equal number of decimal digits in both dividend and divisor)
Hence, the polygon has 7 sides.

The distance covered by the car in one hour = \(\cfrac { 16.8 }{ 0.21 } \) 
Multiply the divisor by 100 to make it a whole number. Hence multiply the dividend also by 100.
Therefore,\(\cfrac { 16.8\times 100 }{ 0.21\times 100 } =\cfrac { 1680 }{ 21 } =80\) 

100 m = 1 km, 1m = \(\cfrac { 1 }{ 1000 } km\) 
Hence, 295 m = \(\\ \\ \\ \cfrac { 295 }{ 1000 } \) m
= 0.295km
Distance travelled by bus  = 1.820 km
Distance covered by walk = 0.295 km
Total distance = 1.820 + 0.295
= 1.820 + 0.295
= 2.115 km
Therefore, the school is situated at the distance of 2.115 km from her house.

First represent the decimal number 7.5 using 7 squares and 5 rectangular strips. Cross out 3 squares from 7 squares and 4 rectangular strips from 5 rectangular strips to get the difference (see Figure). Hence, 7.5 – 3.4 = 4.1.

Here,\(0.16=\cfrac { 16 }{ 100 } \) and \(0.77=\cfrac { 77 }{ 100 } \) 
First shade the region 0.16 and then shade 0.77.
The total shaded area is the sum.
So, 0.16 + 0.77 = 0.93 .