A triangular flag has a height of 15 inches and a base length of 25 inches. Magnolia makes a scale drawing of the flag in which the base length is 10 inches. What is the area of Magnolia’s scale drawing? Solve the problem by computing the actual area from the scale drawing. Show your work.(4 points) not to long.

1 answer

To find the area of Magnolia's scale drawing, we first calculate the area of the actual triangular flag and then use that to find the area of the scale drawing.

  1. Calculate the area of the actual triangular flag:

    The formula for the area \( A \) of a triangle is given by:

    \[ A = \frac{1}{2} \times \text{base} \times \text{height} \]

    For the actual flag, the base is 25 inches and the height is 15 inches:

    \[ A_{\text{actual}} = \frac{1}{2} \times 25 \text{ in} \times 15 \text{ in} = \frac{1}{2} \times 375 \text{ in}^2 = 187.5 \text{ in}^2 \]

  2. Determine the scale factor:

    The base length of Magnolia's scale drawing is 10 inches, while the actual base length is 25 inches. The scale factor \( k \) can be found as follows:

    \[ k = \frac{\text{scale base}}{\text{actual base}} = \frac{10 \text{ in}}{25 \text{ in}} = \frac{2}{5} \]

  3. Calculate the area of the scale drawing:

    The area scales with the square of the scale factor. Therefore, the area of the scale drawing \( A_{\text{scale}} \) can be calculated as:

    \[ A_{\text{scale}} = A_{\text{actual}} \times k^2 = 187.5 \text{ in}^2 \times \left(\frac{2}{5}\right)^2 \] \[ k^2 = \left(\frac{2}{5}\right)^2 = \frac{4}{25} \]

    Then,

    \[ A_{\text{scale}} = 187.5 \text{ in}^2 \times \frac{4}{25} \] \[ = 187.5 \times 0.16 = 30 \text{ in}^2 \]

Thus, the area of Magnolia's scale drawing is \( \boxed{30} \text{ in}^2 \).