What is the area of triangle ABC?

  c)  36√3 square units

Step-by-step explanation:

Using trigonometry, you can find the height CD to be ...

  CD = CB·sin(60°) = 12(√3/2) = 6√3

We know all three angles must be 60°, so all three sides must be the same length. That is, base AB = 12.

Then the area formula can be used.

  A = 1/2bh . . . . . triangle with base b and height h

  A = 1/2(AB)(CD)

  A = 1/2(12)(6√3) = 36√3 . . . square units

d

because parallelagram have all 4 angels the same size dependeing and a rectangle and square are oth parallelogram