SOLUTION: A person 5 feet 3 inches tall casts a 6-foot shadow. At the same time, a lamppost casts an 18 foot shadow. What is the height of the lamppost?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A person 5 feet 3 inches tall casts a 6-foot shadow. At the same time, a lamppost casts an 18 foot shadow. What is the height of the lamppost?       Log On


   



Question 1169111: A person 5 feet 3 inches tall casts a 6-foot shadow. At the same time, a lamppost casts an 18 foot shadow. What is the height of the lamppost?

Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!


At any given time, all the sun's rays are pointing at the same angle.

So, assuming level ground, the ground, the sun's rays, the person, and the lamppost form similar triangles.

In similar triangles, the ratios of corresponding sides are all the same. A shadow 3 times as long (18 feet instead of 6 feet) means the object is 3 times as tall.

Do the arithmetic....