It is given that the triangles are similar, that is,
It is required to find the area of the larger triangle.
Recall that the scale factor, k of similar figures is the ratio of their corresponding sides:
Substitute AC=5 and XZ=15 into the equation:
Hence, the scale factor is 1/3.
Recall that as per the Area of Similar Figures, the ratio of areas for two similar figures with a scale factor, k is:
This implies that:
Substitute the values of the area of triangle ABC and the scale factor into the proportion:
Let the area of ΔXYZ be A, and solve for A in the equation:
The required answer is 432 square ft.
The last choice is the answer.