SOLUTION: The diagram above (not to scale) shows how an elementary student
who is 4 feet tall estimates the height of a lamppost. The student
stands 30 feet from the base of the lamppost a
Algebra.Com
Question 86095: The diagram above (not to scale) shows how an elementary student
who is 4 feet tall estimates the height of a lamppost. The student
stands 30 feet from the base of the lamppost and measures her
shadow from the light as 6 feet long. Approximately how high is
the lamppost?
A. 20 feet
B. 24 feet
C. 36 feet
D. 45 feet
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
To find the unknown side, we can use proportions to find the missing side.
Since we have 2 similar triangles, the ratio of the sides of the triangles are the same. Since the ratio of the sides of the small triangle are the same, this ratio is true:
This basically says: "the ratio of the side with length of 4 to the side of length 6 is equal to the ratio of side x to side 36 (notice the sides of the triangles correspond to one another)
Multiply both sides by 36
Multiply
So the length of the unknown side is 24, which means the lamppost is 24 feet high
So the answer is B)
RELATED QUESTIONS
An elementary student who is 4ft tall estimates the height of a lamppost. The student... (answered by rfer)
A student who is 4 feet tall estimates the height of a lamppost. The student stands 30... (answered by galactus)
146. Height of a post. Betty observed that the lamppost in the front of her house cases a (answered by Earlsdon,stanbon,Edwin McCravy)
a lamppost casts a shadow that is 16 feet long a 2.5 foot high mailbox casts a shadow... (answered by dkppathak)
A person 5 feet 3 inches tall casts a 6-foot shadow. At the same time, a lamppost casts... (answered by greenestamps)
A person 5 feet 3 inches tall casts a 6-foot shadow. At the same time, a lamppost casts... (answered by Solver92311)
I have a solution of 3.1875 meters for this problem but it is in error. (I calculated... (answered by oscargut,stanbon,Earlsdon)
Wilson is 6 ft tall. When Wilson stands 6 feet from a lamppost the shadow he casts is 4... (answered by ankor@dixie-net.com)
Grace is 4 ft. tall and standing in the light of a 20 ft. tall lamppost. her shadow is 8... (answered by scott8148)