Follow these steps to derive the trigonometric area formula.

✓ 1. For △ABD, sin(A) = a/h c/h h/c .

✓ 2. Solve the previous equation for h.
h = c sin(A) a sin(C) .

✓ 3. Use the formula for the area of a triangle, #&{\sf area} = \frac{\sf 1}{\sf 2}bh#&, and divide by multiply by substitute for h to get the trigonometric area formula:


#&{\sf area} = \frac{\sf 1}{\sf 2}bc {\sf \,sin(A)}#&