I’m confused on this one
1 answer:
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Answer:
Tip of the shadow of the girl is moving with a rate of 7.14 feet per sec.
Step-by-step explanation:
Given : In the figure attached, Length of girl EC = 4 ft
Length of street light AB = 25 ft
Girl is moving away from the light with a speed = 6 ft per sec.
To Find : Rate () of the tip (D) of the girl's shadow (BD) moving away from th
light.
Solution : Let the distance of the girl from the street light is = x feet
Length of the shadow CD is = y feet
Therefore, feet per sec. [Given]
In the figure attached, ΔAFE and ΔADE are similar.
By the property of similar triangles,
25x = 21(x + y)
25x = 21x + 21y
25x - 21x = 21y
4x = 21y
y =
Now we take the derivative on both the sides,
=
=
≈ 1.14 ft per sec.
Since w = x + y
Therefore,
= 7.14 ft per sec.
Therefore, tip of the shadow of the girl is moving with a rate of 7.14 feet per sec.
ANSWER:
b) No
c) Yes
EXPLANATION:
b)
3 (-8 + 1) = 3 x -8 + 3
(3 x -8) (3 x +1) = 3 x -8 + 3 (just put left and right sides into calcu separately)
-72 = -21
Both sides are not equal and therefore it isn't a solution.
c)
3 (0.5 + 1) = 3 x 0.5 + 3
(3 x 0.5) (3 x +1) = 3 x 0.5 + 3
4.5 = 4.5
Both sides are equal and thereofre it IS a solution.