SOLUTION: At a point on the ground 60ft from the base of a tree, the distance to the top of the tree is 4 ft more than 2 times the height of the tree. Find the height of the tree.... I know

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: At a point on the ground 60ft from the base of a tree, the distance to the top of the tree is 4 ft more than 2 times the height of the tree. Find the height of the tree.... I know      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 432571: At a point on the ground 60ft from the base of a tree, the distance to the top of the tree is 4 ft more than 2 times the height of the tree. Find the height of the tree....
I know this involves pythagorean theorem but I am stuck with factoring..I can never get it right..
3h^2+16h-3584 this is the max I can get to..need ur help in solving I cant get it thru quadratic funtion formula too pls explain in detail how to get furhter than this thanku

Answer by jorel1380(3719) About Me  (Show Source):
You can put this solution on YOUR website!
From a point on the ground, your line of sight to the top of the tree forms a right triangle from where you are to the base of the tree. Thus, 60^2+h^2=(2h+4)^2.
3600+h^2=(2h+4)^2
3600+h^2=4h^2+16h+16
0=3h^2+16h-3584
0=(3h+112)(h-32)
h=-112/3, 32
Throwing out the negative result, we get the height of the tree to be 32 ft.
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 3x%5E2%2B16x%2B-3584+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%2816%29%5E2-4%2A3%2A-3584=43264.

Discriminant d=43264 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-16%2B-sqrt%28+43264+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2816%29%2Bsqrt%28+43264+%29%29%2F2%5C3+=+32
x%5B2%5D+=+%28-%2816%29-sqrt%28+43264+%29%29%2F2%5C3+=+-37.3333333333333

Quadratic expression 3x%5E2%2B16x%2B-3584 can be factored:
3x%5E2%2B16x%2B-3584+=+3%28x-32%29%2A%28x--37.3333333333333%29
Again, the answer is: 32, -37.3333333333333. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+3%2Ax%5E2%2B16%2Ax%2B-3584+%29