A parallelogram has sides A, B, C, and D. Sides A and B have a length of 5 5 and sides C and D have a length of 4 4. If the angle between sides A and C is (5 pi)/8 5π8, what is the area of the parallelogram?

1 Answer
Feb 27, 2016

4*5*sin((5pi)/8) ~~18.4845sin(5π8)18.48

Explanation:

Sketch
The area of a paralllogram is given by the formula 1/2*Base*Height12BaseHeight

We therefore need to calculate the height hh of the paralleogram.
sin((5pi)/8) = h/Asin(5π8)=hA
:.h = Asin((5pi)/8) = 5sin((5pi)/8)

The base is C which is given as 4

The area is 4*5sin((5pi)/8) ~~18.48