A tree casts a shadow that measures 5 m. At the same time, a meter stick casts a shadow that is 0.4 m long. How tall is the tree?
2006-11-01 14:13:31 · 14 answers · asked by CrazyBlueEyedGirl13 1 in Science & Mathematics ➔ Mathematics
Billy "lick my ***"
2006-11-01 14:18:52 · update #1
write a proportion (two equal fractions) with shadow on top and height on bottom, one for the tree and one for the meter stick:
5/t = 0.4/1 where t = height of tree
Then cross multiply
2006-11-01 14:17:32 · answer #1 · answered by hayharbr 7 · 0⤊ 0⤋
The meter stick can be assumed to be 1 meter tall. Its shadow is 0.4 meters long, or 2/5 as long as the stick is tall. So the tree's shadow should be 2/5 as long as the tree is tall. If 5 meters is 2/5 the height of the tree, then the tree is 12.5 meters tall. There are two ways to calculate this. The best way is to divide 5 by 0.4 to get 12.5; that always works but it's harder to do in your head. I did it by first dividing by 2 to find that 1/5 of the height was 2.5 meters, then multiplying by 5 to get the height.
2006-11-01 14:17:31 · answer #2 · answered by Amy F 5 · 0⤊ 0⤋
These ratio and proportion questions come up a lot on Answers. They usually are assigned after some basic trig lesson as a practical application of trig. I learned how to do this as a child and have used it countless times throughout my life. Its a lesson worth learning. In fact next to basic math trig. is the most interesting and practical of all math topics IMHO. I've included a link below to a similar problem solved by lots of students so you can see different approaches. I try not to do the work for folks but point them to similar situations. I want you to learn and understand how this works. Do a few more problems like it until you really understand how it works. You'll be impressing people at picnics for the rest of your life as you tell them how tall that tree is or how wide that river is. Triangles are everywhere :) Enjoy....
Yack
2006-11-01 14:43:15 · answer #3 · answered by white_yack 3 · 0⤊ 0⤋
what is the ratio of meter stick to shadow?
1 Meter over 0.4 meters.
that same ratio would apply to the tree; you know the ratio and you know how tall the shadow is.
tree is 12.5m high.
2006-11-01 14:16:46 · answer #4 · answered by leikevy 5 · 0⤊ 0⤋
Anyone with a seventh grade education can give the answer, with only pencil and paper; but to be truly certain you should purchase a chainsaw, some gasoline and a long (about 12.6m) tape measure and find out for yourself.
2006-11-01 14:23:25 · answer #5 · answered by Anonymous · 0⤊ 0⤋
We can this by setting up a proportion.
Let x = the height of the tree.
1 divided by 0.4m = x divided by 5m
Next:
Divide each side of the equation by 0.4m to find the height of the tree.
Answer: 12.5m = height of tree.
Guido
2006-11-01 14:21:17 · answer #6 · answered by Anonymous · 0⤊ 0⤋
WITH THE METER STICK BEING 1(ONE) METER I CALCULATE THAT AS 5 DIVIDED BY 0.4 EQUALS 12.5
GOD BLESS
2006-11-01 14:20:31 · answer #7 · answered by thewindowman 6 · 0⤊ 0⤋
12.5 meters. 1/.4 = x/5 solve for x
2006-11-01 14:22:15 · answer #8 · answered by chimodzimodzi 2 · 0⤊ 0⤋
ratio and proportion my friend.
let x the height of the tree.
1/.4=x/5, therefore x=12.5m
2006-11-01 14:17:59 · answer #9 · answered by pao 1 · 0⤊ 0⤋
21. while you're providing THEM calmly then you definitely supply 3 PENCILS, 2 PENS AND a million MARKER. to maintain THEM EVEN you should DIVIDE each and everything calmly yet you in basic terms HAVE 21 MARKERS AND THE OTHERS ARE MULTIPLES OF 21. wish THAT helps
2016-10-21 03:07:08 · answer #10 · answered by ? 4 · 0⤊ 0⤋