Question

The lengths of two sides of a triangle are 6cm and 4cm and the angle between them is 130degree. What is its area?

Answer 1

Area is 1/2 base * height.

Let the side of length 6 be the base.
Extend it so you can drop an altitude from the end of side with length 4.

Now you have a right triangle with hypotenuse=4, base angle = 50 deg (180-130).

So, the height is given by
h/4 = sin(50)
h = 3.06

So, the area is just 1/2 * 3.06 * 6 = 9 approx.