Question

Two opposite sides of a parallelogram each have a length of `2`. If one corner of the parallelogram has an angle of `(2 pi)/3` and the parallelogram's area is `15`, how long are the other two sides?

Answer 1

`b=8.66`

Explanation:

Area of the parallelogram is `=ab sin theta` where `a=2` is the side and `theta=(2pi)/3` and we have to find `b=?`
Therefore
Area`=15=2b sin((2pi)/3)`
or
`bsin((2pi)/3)=15/2`
or
`b(0.866)=7.5`
or
`b=7.5/0.866`
or
`b=8.66`