Question 860831: at a certain time of day a tree that is x meters casts a shadow that is x-46 meters long if the distance from the top of the tree to the end of the shadow is x+4 meters long, what is the height, x, of the tree? ( I'm having a hard time figure what the formula is)?
Answer by mananth(16946)   (Show Source):
You can put this solution on YOUR website! Assuming the tree is vertical at right angles to the ground
then it is a right triangle
The tree,ground and the line from top of tree to the end of shadow.
(x+4)^2=x^2+(x-46)^2
x^2+8x+16=x^2+x^2-92x+2116
x^2-8x-92x-16+2116=0
x^2-100x+2100=0
x^2-70x-30x+2100=0
x(x-70)-30(x-70)=0
(x-70)(x-30)=0
x=30 OR 70
shadow is x-46
so it cannot be 30
so x= 70
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