Area Problems
A man riding a bicycle, completes one lap of a circular field along its circumference at the speed of 14.4 km/h in 1 min 28 s. What is the area of the field?
The man takes 3600 s for 14.4 km The man will take 88 s for 14.4 x (88/3600) = 352/1000 km = 352 m Now, circumference of circular field = 352 m ? 2?r = 352 m2 x (22/7) x r = 352 ? r = 56 m Therefore, area of the field = ?r2= (22/7) x 56 x 56 = 8 x 22 x 56 m2= 9856 sq m.
Area of a triangle formed by joining the mid point of the sides of the triangle is 1/4th of area of the original triangle .So area of ? DEF = 36/ 4 = 9 m2
Area of square room = (10)2 = 100 sq m= 100 x (100)2 sq cm= 100 x 100 x 100 sq cmNow, area of tiles = (50)2 = 50 x 50 sq cm? Number of tiles needed = (Area of square room) / (Area of tile)= (100 x 100 x 100) / (50 x 50) = 400Hence, 400 tiles will be needed.
In a triangleSum of two sides is always greater than 3rd side i.e., x < 25 + 15 = 40 .....(i)Difference of two sides is always less than 3rd side i.e., 25 - 15 = 10 < x ...(ii) From Eqs. (i) and (ii) , we get 10 < x < 40
Let original length = x metres and original breadth = y metres. Original area = xy sq.m Increased length = 120 100 and Increased breadth = 120 100 New area = 120 100 x * 120 100 y = 36 25 x y m 2 The difference between the Original area and New area is: 36 25 x y - x y 11 25 x y Increase % = 11 25 x y x y * 100 = 44%
EXAMIANS