Use the image to answer the question.

An illustration shows a triangular prism. The front triangular face is visible. The left rectangular face is visible. The sides and edges that are not visible are indicated by dashed lines. Parts are labeled with measurements. All sides of the triangle measure 10 centimeters. The perpendicular height from the top vertex of the triangle to the base measures 8 centimeters. The width of the rectangular face measures 6 centimeters.

Solve for the surface area of the triangular prism.

Responses:

280 square centimeters

180 square centimeters

260 square centimeters

320 square centimeters

1 answer

To find the surface area of the triangular prism, we need to calculate the surface area of the triangular bases and the rectangular sides.

  1. Area of the triangular base: The triangular base is an equilateral triangle with each side measuring 10 cm. The formula for the area of an equilateral triangle is given by: \[ A = \frac{\sqrt{3}}{4} s^2 \] Where \( s \) is the length of a side.

    For our triangle: \[ A = \frac{\sqrt{3}}{4} (10)^2 = \frac{\sqrt{3}}{4} \cdot 100 = 25\sqrt{3} , \text{square centimeters} \]

    Since there are two triangular bases: \[ \text{Total area of two triangular bases} = 2 \cdot 25\sqrt{3} = 50\sqrt{3} , \text{square centimeters} \]

  2. Area of the rectangular faces: The prism has three rectangular faces:

    • Two rectangles measuring \( 10 , \text{cm} \times 6 , \text{cm} \)
    • One rectangle measuring \( 10 , \text{cm} \times 8 , \text{cm} \) (the height of the triangle multiplied by the prism’s height)

    The area of each rectangular face:

    • Area of the two \( 10 , \text{cm} \times 6 , \text{cm} \) faces: \[ 2 \cdot (10 \cdot 6) = 2 \cdot 60 = 120 , \text{square centimeters} \]

    • Area of the \( 10 , \text{cm} \times 8 , \text{cm} \) face: \[ 10 \cdot 8 = 80 , \text{square centimeters} \]

    So, total area of the rectangular faces: \[ 120 + 80 = 200 , \text{square centimeters} \]

  3. Total surface area: Now, we can calculate the total surface area of the prism: \[ \text{Total surface area} = \text{Area of triangular bases} + \text{Area of rectangular faces} \]

    Given \( \sqrt{3} \approx 1.732 \): \[ 50\sqrt{3} \approx 50 \cdot 1.732 \approx 86.6 , \text{square centimeters} \] Therefore, the approximate total surface area: \[ \text{Total surface area} \approx 86.6 + 200 \approx 286.6 , \text{square centimeters} \]

However, noticing that the choices provided do not include this value suggests that the area of the triangle previously calculated should be re-evaluated.

Let's use the given height of the triangle which is 8 cm: The area of the triangle can also be calculated as: \[ A = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 10 \times 8 = 40 , \text{square centimeters} \]

So the total area of two triangular bases becomes: \[ \text{Total area of two triangular bases} = 2 \cdot 40 = 80 , \text{square centimeters} \]

Putting that back into our total surface area: \[ \text{Total surface area} = 80 + 200 = 280 , \text{square centimeters} \]

Thus, the correct response for the surface area of the triangular prism is: 280 square centimeters.