Hi Steve,

You helped me with a question earlier today about finding surface area of a triangular prism with the base being an equilateral triangle . I got the answer 386.6 Is this correct.? I tried to follow your equation and am having a bit of trouble. Thanks for all your help.

That's what I get.

if you have a hard time figuring the area of an equilateral triangle, it's time for some further review. It's a 30-60-90 right triangle on each side of the altitude because each angle of the main triangle is 60 degrees.

Hi there! I'm glad I could help you earlier. Let's check if your answer of 386.6 for the surface area of a triangular prism with an equilateral triangle base is correct.

To find the surface area of a triangular prism, you need to calculate the area of all its faces and then add them up.

For a triangular prism with an equilateral triangle base, we have two identical triangular bases and three rectangular lateral faces.

To find the area of the triangular base, you can use the formula:

Area = (side length)^2 * (√3 / 4)

Since you mentioned that the base is an equilateral triangle, all three sides are equal. Therefore, you can use the notation "s" to represent the side length of the triangle.

Now, to find the area of the triangular base, you substitute the value of "s" in the formula:

Area = (s)^2 * (√3 / 4)

Next, multiply this area by 2 because the prism has two identical triangular bases:

Total area of the triangular bases = 2 * (s)^2 * (√3 / 4)

To find the area of each rectangular lateral face, you need to multiply the length and width.

The length of the lateral face is equal to the perimeter of the triangular base, which is 3s. The width is equal to the height of the prism, which we'll call "h."

Therefore, the area of each rectangular lateral face is given by:

Area of each rectangular lateral face = (3s) * h

To find the total area of the three rectangular lateral faces, you multiply this area by 3:

Total area of the rectangular lateral faces = 3 * (3s) * h = 9sh

Finally, to find the total surface area, you add the area of the two triangular bases and the area of the three rectangular lateral faces:

Total surface area = Total area of the triangular bases + Total area of the rectangular lateral faces

= 2 * (s)^2 * (√3 / 4) + 9sh

Now let's check your answer of 386.6 for the total surface area. It is important to make sure you used the correct values for "s" and "h."

If you provide me with the values you used for the side length and height, we can verify if your answer is correct together.