SOLUTION: In parallelogram ABCD, base AD is 15 units long and base AB is 8 units long. What are the height and area of ABCD if the measure of angle DAB is 20 degrees? This is a Geometry

Algebra ->  Parallelograms -> SOLUTION: In parallelogram ABCD, base AD is 15 units long and base AB is 8 units long. What are the height and area of ABCD if the measure of angle DAB is 20 degrees? This is a Geometry       Log On


   



Question 604160: In parallelogram ABCD, base AD is 15 units long and base AB is 8 units long. What are the height and area of ABCD if the measure of angle DAB is 20 degrees?
This is a Geometry question, but it is labeled "Using Trigonometry". I've only ever done trigonometry with right triangles, not parallelograms.
I know that the area of a parallelogram is base * height, and that the base of ABCD is 15. I'm just stumped when it comes to finding the height.

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
if the parallelogram is sitting on AB, you can draw an altitude (height) from the end of AD down to AB

this forms a right triangle, with AD as the hypotenuse

you know angle A, so to find the height ___ h = 8 * sin(20º)