Question

a light is on the ground 20m from a building. A man 2m tall walks from the light directly toward the building at 1m/s how fast is the length of his shadow on the building changing when he is 14m from the building?
Don't know how to solve this :(

Answer 1

@dolphins121 still alive? cx

Answer 2

yes

Answer 3

@Brostep0s

Answer 4

What type of math are you currently studying.

Answer 5

Calculus

Answer 6

What lesson are you studying?

Answer 7

@dolphins121

Answer 8

uhm velocity, speed, acceleration. Basically physics related stuff.

Answer 9

@Brostep0s

Answer 10

Assuming the boy and the lamp are vertical, we have 2 similar triangles

Answer 11

The pieces form the proportion
ED/BC = AE/AB

Answer 12

you know how tall the man is, and you know how long the shadow is, right? That gives you the base and height of the smaller triangle, plus (with a little arithmetic) the base of the larger triangle, and you use a proportion to find the height of the larger triangle

Answer 13

Please read the configuration of the problem. similar triangles is the way to go.