The radius of the wheel of a vehicle is 70 cm. The wheel makes 10 revolutions in 5 seconds. The speed of the vehicle is?

? Area of square = Area of circle
? x² = ?r²
? x/r = ??
= ? ? : 1

Ratio of the areas = area of original square / area of new square
= [ d² / 2 ] / [ (2d)² / 2 ] = 1/4
? New area becomes 4 fold.

s = (13 + 14 + 15 ) / 2 = 21,
s-a = 8 ,
s-b = 7,
s-c= 6

? Area to be painted = ? [s(s-a) (s-b) (s-c)]
=? [21 x 8 x 7 x 6] m²
= 84 m²

? Cost of painting = Rs. (84 x 8.75) = Rs. 735

Let lateral side = (5y) cm and base = (4y) cm
? perimeter = 5y + 5y + 4y = 14
?y = 1

So, the sides are 5 cm , 5 cm and 4 cm

Now s= 1/2 (5 + 5 + 4) cm = 7 cm
(s-a) = 2 cm
(s-b) = 2 cm and
(s-c) = 3 cm

? Required Area = ? (7 x 2 x 2 x 3) cm²

=2?21 cm²

? s= (13 + 5 + 12) / 2 cm
= 15cm

s-a = 2 cm,
s-b = 10 cm and
s-c = 3 cm

? Area = ? (15 x 2 x 10 x 3 ) cm²
= 30 cm²

? (12 x h) / 2 = 30
? h = 5 cm

Area = ?r² = 0.49?
? r = 0.7 m

Number of revolutions = total distance / circumference
= (1.76 x 1000) / (2 x 22/7 x 0.7)
= 400

Number of round = total distance / circumference of wheel.
= (4 x 1000) / ?d
= (4 x 1000) / ( 22/7 x 7/11)
= 2000

Distance covered in one revolution = total distance travelled / total number of revolution.
= ( 88 x 1000) / 1000 m
= 88 m

We know that the distance covered in one revolution = circumference of the wheel.
? ?d = 88
? 22d / 7 = 88
? d = 28 m

Distance travelled in 1 revolution = circumference of the wheel
= ?d
= ( 22/7 ) x 63
= 198 cm

So the distance travelled in 100 revolutions = 100 x distance travelled in 1 revolution
= 100 x 198 cm
= 19800 cm
= 198 m

Let outer radius be R and inner radius be r.
Then from question
2?R - 2?r = 66
? 2? (R-r) = 66
? (2 x 22)/7 x (R - r) = 66
? (R-r) = (66 x 7) / 44
= 10.5 m