Question

Find the surface area of the figure below. The triangle is an equilateral triangle.

A. 330
B. 321.5
C. 115
D. 307.5

Hold up gota draw it quick:)

Answer 1

sorry this is a terrible drawing its supposed to be an equilateral triangle

Answer 2

The SA of a triangular prism can be expressed as:

SA=bh + (S1+ S2 + S3)H

Answer 3

I got C for my answer, is that correct?

Answer 4

hello? guys would C be my answer:)?

Answer 5

@e.cociuba

Answer 6

hello!?

Answer 7

Think of it like this. There is 3 rectangles and 2 triangles. The area of a rectangle is L x W and area of a triangle is BH/2. Find each area and them up.

@katlin95

Answer 8

ohh now im getting A for my answer now.

Answer 9

I used this formula @dimensionx gave me

Answer 10

We know that these are equilateral triangles, which means if one side is 5, then all sides are 5. We also know that the rectangle shares a side with the triangle, and if that side of the triangle is 5, then the width of the rectangle is also 5. So now we know the length of rectangles is 20, width is 5. And for the triangles, each side is 5. We can find the height of the triangle using Pythagorean theorem and then find the area of the triangles.

Answer 11

can you give me the solution to solve?

Answer 12

I want you to try. All the information is there. You just need to use it to calculate the areas.

Answer 13

alright I got 307.5

Answer 14

ohhhhh hahaha! its B

Answer 15

correct right?

Answer 16

That's incorrect. We know that all rectangles are 20 x 5, which means that the area of each is 100. Since there is 3 of them, then the combined area is 300.

Now to find the area of the equilateral triangle, there is 2 ways to do this. Either you can find the height using Pythagorean theorem which takes some time, or you can use this handy-dandy formula for the AREA OF AN EQUILATERAL TRIANGLE:\[AREA=\frac{ \sqrt{3} }{ 4 }a^2\]Where 'a' is the side length of the equilateral triangle.
@katlin95

Answer 17

Sorry, the formula is actually with a 4 in the denominator, not a 2. I forgot that lol

Answer 18

And you are correct, it is B. Good job!

@katlin95

Answer 19

?

Answer 20

B is the right answer.