Question

Geometry word problem.

Answer 1

Do I use Sine or Cosine to solve?

Answer 2

so all sides are equal in length.

draw a diagonal and find the area of the lower triangle using

\[Area = \frac{1}{2} \times a \times b \times \sin(C)\]

in your question a = 7, b = 7 and C = 60

when you get the answer just double it as the upper triangle is congruent

hope it helps