• Jun 21st 2009, 10:59 PM
LOL
A 2.5 m pole casts a shadow that measures 3m. A nearby tree casts a shadow that is 8.4 m long. Find the height of the tree.
• Jun 21st 2009, 11:05 PM
Chris L T521
Quote:

Originally Posted by LOL
A 2.5 m pole casts a shadow that measures 3m. A nearby tree casts a shadow that is 8.4 m long. Find the height of the tree.

The best way to do this problem is to construct similar triangles.

When you construct the triangles, the ratios of the heights and lengths should be proportional.

So if we let $\displaystyle h$ represent the height of the tree, we see that $\displaystyle \frac{2.5}{h}=\frac{3}{8.4}$ (or we could have done $\displaystyle \frac{2.5}{3}=\frac{h}{8.4}$; try to see why)

Can you try to finish from here?
• Jun 21st 2009, 11:13 PM
LOL
Quote:

Originally Posted by Chris L T521
The best way to do this problem is to construct similar triangles.

When you construct the triangles, the ratios of the heights and lengths should be proportional.

So if we let $\displaystyle h$ represent the height of the tree, we see that $\displaystyle \frac{2.5}{h}=\frac{3}{8.4}$ (or we could have done $\displaystyle \frac{2.5}{3}=\frac{h}{8.4}$; try to see why)

Can you try to finish from here?

Alright so, you draw your diagram, and then we got 2.5/3= h/8.4 then from there i got the height of the tree being 10.08m rounded to 10.0m. Is this right, its going to be a long night, cramming for my math exam, haha...
• Jun 21st 2009, 11:16 PM
Chris L T521
Quote:

Originally Posted by LOL
Alright so, you draw your diagram, and then we got 2.5/3= h/8.4 then from there i got the height of the tree being 10.08m rounded to 10.0m. Is this right, its going to be a long night, cramming for my math exam, haha...

hm..I get $\displaystyle h=\frac{2.5\times 8.4}{3}=7$...
• Jun 21st 2009, 11:25 PM
LOL
Quote:

Originally Posted by Chris L T521
hm..I get $\displaystyle h=\frac{2.5\times 8.4}{3}=7$...

haha, thanks man, im not really numbers smart, just need all the help i can get to pass my exam, thanks for the help...