The side of a rhombus is 26 m and length of one of its diagonals is 20 m. The area of the rhombus is_______?

A. 529 sq m
B. 240 sq m
C. 260 sq m
D. 480 sq m

Explanation:
262 – 102 = 242
d1 = 20 d2 = 48
1/2 * 20 * 48 = 480