- #1
Hypnos_16
- 153
- 1
Homework Statement
A man 6 feet tall walks at a rate of 5 feet per second away from a light that is attached to a pole 15 feet above the ground. At what rate is the length of his shadow changing when he is 30 feet from the base of the pole?
I get that this is really like a two similar triangle problem, the way the light is shining and the shadow cast by the man
so i called the larger triangle ∆abc
and the smaller ∆xyz
The larger is the one that is caused by the light
a (x value) = 30 feet (Distance from Light Pole) + Shadow Length
b (y value) = 15 feet (Light Pole)
c (z value) = the Pythagorean value
The smaller triangle
x (x value) = Shadow Length
y (y value) = 6 feet (Man's Height)
z (z value) = the Pythagorean Value
Now i have figured out some values.
a = 30 feet
b = 15 feet
y = 6 feet
c2 = (302 + (b - y)2)
c = √981
Homework Equations
I assume a2 + b2 = c2
since it's a right triangle
but i don't have enough values
The Attempt at a Solution
i don't really have one. Sorry if that was confusing. I can try and clarify if need be.