Surface area of the pyramid= 4*(area of the triangle) + area of the square
Area of the triangle = (1/2)*base*height=(1/2)*5*5= 25/2 in²
Area of the square = 5*5 =25 in²
Surface area of the pyramid = 4*(25/2) + 25=2*25 + 25=75 in²
So this first wants you to find where sin is √3/2 when θ is between π and 3π/2. θ would therefore be located at 2π/3.
Now plug in the value of θ for cosine:
cos (2π/3) = -1/2
And tangent:
tan (2π/3) = -√3/3
2 because rise/run so 8/4 which=2
