In the regular triangular pyramid below, x = 5.9 mm and s = 14 mm.

*Note: Figure not drawn to scale.

What is the approximate surface area of the triangular pyramid?
I need to find the area of the bottom triangle I have the rest.

Question

In the regular triangular pyramid below, x = 5.9 mm and s = 14 mm.


*Note: Figure not drawn to scale.

What is the approximate surface area of the triangular pyramid?
I need to find the area of the bottom triangle I have the rest.

anonymous · Answer

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goformit100 · Answer

What is the approximate surface area of the triangular pyramid? I need to find the area of the bottom triangle I have the rest.

anonymous · Answer

The 3 bigger triangles= 123.9 So what's the bottom?

anonymous · Answer

Surface area. The total of all the shapes area added up.

anonymous · Answer

@jim_thompson5910

anonymous · Answer

I narrowed the answer to two choices. 
154.05 mm^2
138.97 mm^2

anonymous · Answer

@FlaCaLOL  do you know how to do this?

anonymous · Answer

Got it!
138.97mm^2

jim_thompson5910 · Answer

is the base an equilateral triangle?

anonymous · Answer

I believe.

jim_thompson5910 · Answer

if so, then

A = (1/4)*s^2*sqrt(3)

A = (1/4)*5.9^2*sqrt(3)

A = 15.0731721528681

which is the area of the triangular base

jim_thompson5910 · Answer

Add this to the lateral surface area you got to get

123.9 + 15.0731721528681 = 138.973172152869

which rounds to 138.97

jim_thompson5910 · Answer

So you got it right (assuming the base is an equilateral triangle)