**CONCEPT:** Area of a triangle = (1/2)* a* b* sin (angle included between a and b) where

a and b are two sides of the triangle.

**SOLUTION:**

The sine formula for area can also be used here to find the area.

Sine formula for area = (1/2)*a*b*sin(included angle)

= (1/2)*5*12*sin 90

=30 sq units (OPTION D)