Question

Find the surface area of the triangular pyramid. The side lengths of the base are equal.

Answer 1

Answer:

133.5 cm²

Step-by-step explanation:

We have

three triangles with the base b = 10cm and the height h₁ = 6cm

one triangle with the base b = 10cm and the height h₂ = 8.7cm.

The formula of an area of a triangle:

$A=\dfrac{b\cdot h}{2}$

b - base

h - height

Substitute:

$A_1=\dfrac{(10)(6)}{2}=\dfrac{60}{2}=30\ cm^2$

$A_2=\dfrac{(10)(8.7)}{2}=\dfrac{87}{2}=43.5\ cm^2$

$S.A.=3A_1+A_2\\\\S.A.=3(30)+43.5=90+43.5=133.5\ cm^2$