Myk is 5 feet and 2 inches tall, and their shadow is 84 inches tall. The flagpole next to them has a shadow that is 31 feet long. Myk uses similar triangles to find the height of the flagpole. Can you calculate the height of the flagpole to the nearest foot?

A. 23 inches
B. 23 feet
C. 374 feet
D. 17 feet

1 answer

To find the height of the flagpole using similar triangles, we can set up a proportion based on Myk's height and shadow length compared to the flagpole's height and shadow length.

First, we need to convert Myk's height to inches. Myk's height is 5 feet and 2 inches.

1 foot is 12 inches, so: \[ 5 \text{ feet} = 5 \times 12 = 60 \text{ inches} \] Adding the remaining 2 inches: \[ \text{Myk's height} = 60 + 2 = 62 \text{ inches} \]

Now, we can set up our proportion. Let \( h \) be the height of the flagpole in inches. We know:

  • Myk's height: 62 inches
  • Myk's shadow: 84 inches
  • Flagpole shadow: 31 feet (which is \( 31 \times 12 = 372 \text{ inches} \))

Now, we can set up the proportion: \[ \frac{\text{Myk's height}}{\text{Myk's shadow}} = \frac{\text{Flagpole height}}{\text{Flagpole shadow}} \] Which translates to: \[ \frac{62}{84} = \frac{h}{372} \]

Now, we can cross-multiply to solve for \( h \): \[ 62 \times 372 = 84 \times h \] Calculating \( 62 \times 372 \): \[ 62 \times 372 = 23064 \] Now substituting back: \[ 23064 = 84h \] To solve for \( h \), divide both sides by 84: \[ h = \frac{23064}{84} \approx 274 \]

Now converting \( h \) from inches to feet (since 1 foot = 12 inches): \[ \frac{274}{12} \approx 22.83 \text{ feet} \]

Rounding to the nearest foot gives us approximately 23 feet.

Thus, the height of the flagpole is: B. 23 feet.