Here is a triangular pyramid and its net.
The lateral faces are congruent triangles. The base (shaded) is an equilateral triangle.
(All lengths are in millimeters.)

a) Area of the base of the pyramid =

b) Area of one lateral face =

c) Lateral Surface Area =

d) Total Surface Area =

Step-by-step explanation:

We are given the following dimensions of the triangular pyramid:

Side of triangular base = 6mm

Height of triangular base = 5.2mm

Base of lateral face (triangular) = 6mm

Height of lateral face (triangular) = 8mm

a) To find Area of base of pyramid:

We know that it is a triangular pyramid and the base is a equilateral triangle.

b) To find area of one lateral surface:

Base = 6mm

Height = 8mm

Using equation (1) to find the area:

c) To find the lateral surface area:

We know that there are 3 lateral surfaces with equal height and equal base.

Hence, their areas will also be same. So,

d) To find total surface area:

Total Surface area of the given triangular pyramid will be equal to Lateral Surface Area + Area of base

Hence,

a) Area of the base of the pyramid =

b) Area of one lateral face =

c) Lateral Surface Area =

d) Total Surface Area =

a is the right answer

step-by-step explanation :

we know that

the measurement of the outer angle is the semi-difference of the arcs which comprises

in this problem

m< xzy is the outer angle

substitute the values

the measure of angle xoy is equal to

> by central angle

substitute the value