Use the image to answer the question.

One smaller and one larger triangle side by side.

A triangle has a base of 8 cm and a height of 3 cm. The triangle is dilated by a scale factor of 3. Calculate and compare the areas of the dilated triangle and the original triangle.

(1 point)
Responses

The original triangle has an area of 24 cm2
and the dilated triangle has an area of 36 cm2
; therefore, the dilated triangle has an area 1.5 times the size of the original triangle.
The original triangle has an area of 24 cm squared and the dilated triangle has an area of 36 cm squared ; therefore, the dilated triangle has an area 1.5 times the size of the original triangle.

The original triangle has an area of 24 cm2
and the dilated triangle has an area of 108 cm2
; therefore, the dilated triangle has an area 4.5 times the size of the original triangle.
The original triangle has an area of 24 cm squared and the dilated triangle has an area of 108 cm squared ; therefore, the dilated triangle has an area 4.5 times the size of the original triangle.

The original triangle has an area of 12 cm2
and the dilated triangle has an area of 108 cm2
; therefore, the dilated triangle has an area 9 times the size of the original triangle.
The original triangle has an area of 12 cm squared and the dilated triangle has an area of 108 cm squared ; therefore, the dilated triangle has an area 9 times the size of the original triangle.

The original triangle has an area of 12 cm2
and the dilated triangle has an area of 36 cm2
; therefore, the dilated triangle has an area 3 times the size of the original triangle.
The original triangle has an area of 12 cm squared and the dilated triangle has an area of 36 cm squared ; therefore, the dilated triangle has an area 3 times the size of the original triangle.
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1 answer

To find the areas of the triangles, we first calculate the area of the original triangle, followed by the area of the dilated triangle.

  1. Area of the original triangle: The formula for the area of a triangle is given by: \[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \] For the original triangle:

    • Base = 8 cm
    • Height = 3 cm

    Substituting the values: \[ \text{Area} = \frac{1}{2} \times 8 \times 3 = \frac{1}{2} \times 24 = 12 \text{ cm}^2 \]

  2. Area of the dilated triangle: The scale factor of dilation is 3. When a triangle is dilated by a scale factor \(k\), the area of the new triangle is \(k^2\) times the area of the original triangle. Here, \(k = 3\): \[ \text{Area}{\text{dilated}} = k^2 \times \text{Area}{\text{original}} = 3^2 \times 12 = 9 \times 12 = 108 \text{ cm}^2 \]

  3. Comparison of the areas: The original triangle has an area of 12 cm² and the dilated triangle has an area of 108 cm². To find how many times larger the dilated triangle is compared to the original, we calculate: \[ \frac{\text{Area}{\text{dilated}}}{\text{Area}{\text{original}}} = \frac{108}{12} = 9 \]

Based on the calculations, the original triangle has an area of 12 cm², and the dilated triangle has an area of 108 cm², making the dilated triangle 9 times larger than the original.

Thus, the correct response is: The original triangle has an area of 12 cm² and the dilated triangle has an area of 108 cm²; therefore, the dilated triangle has an area 9 times the size of the original triangle.