Question

For a project in his Geometry class, Mamadou uses a mirror on the ground to measure the height of his school's football goalpost. He walks a distance of 13.75 meters from his school, then places a mirror on flat on the ground, marked with an X at the center. He then steps 2.6 meters to the other side of the mirror, until he can see the top of the goalpost clearly marked in the X. His partner measures the distance from his eyes to the ground to be 1.75 meters . How tall is the goalpost? Round your answer to the nearest hundredth of a meter .

Answer 1

Answer:

Height of the goalpost is 9.25 m.

Step-by-step explanation:

As per the rule of reflection in physics,

Angle of incidence = Angle of reflection

As we can see in the picture attached, both the angles (θ) are equal.

m∠ACB = m∠ECD = 90° - θ

m∠ABC = m∠ADC = 90°

Therefore, both the triangles ΔABC and ΔEDC will be similar.

And by the property of similar triangles, their corresponding sides will be proportional.

$\frac{AB}{ED}= \frac{CB}{CD}$

$\frac{1.75}{ED}=\frac{2.6}{13.75}$

ED = $\frac{1.75\times 13.75}{2.6}$

ED = 9.25 m

Height of the goalpost is 9.25 m.