Answer :
There are two congruent triangles that are being formed from the lamppost, the light, the ground and the man. Always try to draw a picture for these types of problems. It helps a lot when solving. Your answer should be about 4.3ft

Answer:
4.29 feet ( approx )
Step-by-step explanation:
Let x be the length of the shadow of man,
Given,
The height of the man = 6 feet,
The height of the lamppost = 20 foot,
Distance of the man from the lampost = 10 feet,
By making the diagram,
We found two similar triangles in which first triangle having sides 6 and x,
Second triangle having sides 20 and x + 10,
∵ The corresponding sides of similar triangle are in same proportion,
[tex]\implies \frac{x}{x+10}=\frac{6}{20}[/tex]
[tex]20x = 6x + 60[/tex]
[tex]20x - 6x = 60[/tex]
[tex]14x = 60[/tex]
[tex]\implies x = \frac{60}{14}=4.28571428571\approx 4.29[/tex]
Hence, the length of the shadow is approximately 4.29 feet.
