Question

What is the missing length l
of the triangular prism if the surface area is 524 square centimeters? The triangles have a base of 8 and a height of 6. The rectangles are 10

(1 point)
Responses

16 cm
16 cm

8 cm
8 cm

17 cm
17 cm

10 cm
10 cm

Answers

Answered by GPT-4o mini
To find the missing length \( l \) of the triangular prism, we first need to calculate the surface area of the prism.

1. **Calculate the area of the triangular base:**
The area \( A \) of a triangle is given by the formula:
\[
A = \frac{1}{2} \times \text{base} \times \text{height}
\]
In this case, the base is 8 cm and the height is 6 cm. So,
\[
A = \frac{1}{2} \times 8 \times 6 = 24 \text{ cm}^2
\]

2. **Calculate the total area of the two triangular bases:**
Since there are two triangular bases in a prism, their combined area is:
\[
\text{Total area of triangles} = 2 \times 24 = 48 \text{ cm}^2
\]

3. **Calculate the area of the three rectangular sides:**
- The first rectangular side (length \( l \), height from triangle) has an area:
\[
\text{Area} = l \times 8
\]
- The second rectangular side also has an area:
\[
\text{Area} = l \times 6
\]
- The third rectangular side has a base of the prism, which is the length given as 10 cm:
\[
\text{Area} = 10 \times l
\]

4. **Combine the areas to find the total surface area:**
The total surface area \( S \) of the prism is the sum of the areas of the two triangular bases and the three rectangular faces:
\[
S = \text{Area of triangles} + \text{Area of rectangles}
\]
Substituting in the areas calculated:
\[
S = 48 + (l \times 8) + (l \times 6) + (10 \times l)
\]
This simplifies to:
\[
S = 48 + 24l
\]

5. **Set the total surface area equal to the given surface area:**
We are given that the total surface area is 524 cm\(^2\):
\[
24l + 48 = 524
\]

6. **Solve for \( l \):**
First, subtract 48 from both sides of the equation:
\[
24l = 524 - 48
\]
\[
24l = 476
\]
Now, divide both sides by 24:
\[
l = \frac{476}{24}
\]
\[
l = 19.8333 \text{ cm}
\]

None of the given responses (16, 8, 17, or 10 cm) is correct for this calculation. Therefore, the answer is not among the options provided if the calculations are correct.

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