Question

area = c * b * sin a / 2

Answer 1

You have the lengths of two sides and the measure of the included angle. So, you can use the formula R=0.5prsin(Q) where p and r are the lengths of the sides opposite to the vertices P and R respectively.

Using the formula the area, R=0.5(3)(4)sin(145°)

Simplify.

R=6sin(145°)

     ≈6(0.5736)

     ≈3.44

Therefore, the area of ΔPQR is about 3.44 sq. cm.