# Area of triangle

1. Jan 29, 2010

### huntingrdr

1. The problem statement, all variables and given/known data
Show that the area of a triangle with sides of lengths a and b with included angle theta is...

A = 1/2 a*b*sin(theta)

I am not sure what this question is really asking. Any help?

2. Relevant equations

3. The attempt at a solution

2. Jan 29, 2010

### dacruick

i believe strongly that you can figure it out.

3. Jan 29, 2010

### huntingrdr

If the area of a triangle is 1/2 b*h, and sin theta = opp/hyp, then that means a=h and b=b. Correct? Now how do I prove that the area is 1/2 a*b*sin(theta). I drew a right triangle and labeled the sides a and b, and the angle theta.

4. Jan 29, 2010

### GunnaSix

It isn't necessarily a right triangle. Try making side "a" the base and dropping a height "h" down from the opposite corner.

5. Jan 29, 2010

### Staff: Mentor

Furthermore, since the OP's problem states only that it is a triangle, he/she should not assume that it is a right triangle.