Area Problems
Radhika runs along the boundary of a rectangular park at the rate of 12 km/hr and completes one full round in 15 minutes. If the length of the park is 4 times its breadth , the area of the park is?
Speed = 12 x (5/18) m/sec =10/3 m/sec there4; perimeter = (10/3) x 15 x 60 m=3000 m? 2( a + 4a) = 3000 m? a = 300 mSo, length = 1200 m and breadth = 300 m ? Area = (1200 x 300 ) m2 = 360000m2
Let the side of the square(ABCD) be x metres. Then, AB + BC = 2x metres. AC = √2x = (1.41x) m. Saving on 2x metres = (0.59x) m. Saving % = ❨ 0.59x x 100 ❩% = 30%
Area of park = 100 x 100 = 10000 m2Area of circular lawn = Area of park - area of park excluding circular lawn= 10000 - 8614 = 1386Now again area of circular lawn = (22/7) x r2 = 1386 m2? r2 = (1386 x 7) / 22= 63 x 7= 3 x 3 x 7 x 7? r = 21 m
EXAMIANS