Answer:
105
For the 4 triangular faces, find the area with 1/2 × base × height = 1/2 × 5 × 8 = 20
4 triangles -> 20 × 4 = 80
The area of the square base is 25
80 + 25 - 105
80
Triangle’s interior angles total measure always equal 180.
40+60=100
180-100=80
We know that :
⊕ Sum of the three angles in a triangle should be equal to 180°
Given : Angle BAC = 50° and Angle ABC = 75°
⇒ Angle BAC + Angle ABC + Angle ACB = 180°
⇒ 50° + 75° + Angle ACB = 180°
⇒ 125° + Angle ACB = 180°
⇒ Angle ACB = 180° - 125°
⇒ Angle ACB = 55°