Answer:
480 ft
Step-by-step explanation:
To find the width (x), apply the similarity theorem of two similar triangles, which says that the corresponding lengths of two similar triangles are proportional.
Thus:
x/72 = 80/12
Cross multiply
12 × x = 80 × 72
12x = 5,760
12x/12 = 5,760/12
x = 480
Width of the canyon = x = 480 ft