A parallelogram has sides 30m and 14m and one of its diagonals is 40m long. Then its area is

• A. 336
• B. 436
• C. 236
• D. 136

Answer: (A)

let ABCD be the given parallelogram  area of parallelogram ABCD = 2 x (area of triangle ABC)  now a = 30m, b = 14m and c = 40m  s=1/2 x (30+14+40) = 42    Area of triangle ABC =  s s - a s - b s - c      = 42 12 28 2 = 168sq m  area of parallelogram ABCD = 2 x 168 = 336 sq m