A 5 ft-tall person stands on level ground at a point ft from the base of a 20 ft…

MATHEMATICS · Subjective · CBSE · Mathematics · Triangles · Triangles

Problem

A 5 ft-tall person stands on level ground at a point

x

ft from the base of a 20 ft streetlamp and casts a shadow of length

s

ft along the ground. Explain why the proportion

\dfrac{20}{x+s}=\dfrac{5}{s}

is valid in this situation.