SOLUTION: I have two questions that I have been toying with and they are driving me nuts. Can someone help please 1) a 10 inch tv has a width of 8 inches. WHat is its height? 2)Find

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: I have two questions that I have been toying with and they are driving me nuts. Can someone help please 1) a 10 inch tv has a width of 8 inches. WHat is its height? 2)Find       Log On


   

Question 196285: I have two questions that I have been toying with and they are driving me nuts. Can someone help please
1) a 10 inch tv has a width of 8 inches. WHat is its height?
2)Find a polynomial for the perimeter and for area.( shape is a rectangle)
top of the rectangle is x+6 the side is just the letter x.
Thanks in advance

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Well, I hope I'm in time to rescue your sanity. (lol)
1) The size of a TV is designated by the length of the screen's diagonal.
A 10" TV then has a diagonal of 10".
If the width of a 10" TV is 8", its height can be found by using the Pythagorean theorem: c%5E2+=+a%5E2%2Bb%5E2 and in this case, c (the diagonal) is 10" and a is 8", so b would be the height of the TV.
c%5E2+=+a%5E2%2Bb%5E2 Substitute c = 10, a = 8, and solve for b, the height.
10%5E2+=+8%5E2+%2B+b%5E2
100+=+64%2Bb%5E2 Subtract 64 from both sides of the equation.
36+=+b%5E2 Take the square root of both sides.
b+=+6 or b+=+-6 Discard the negative solution as the height can only be a positive value.
The height of the TV is 6"
2) Start with the formula for the perimeter of a rectangle: A+=+2%28L%2BW%29 where L = length and W = width.In this problem, L = x+6 and W = x, so...
P+=+2%28%28x%2B6%29%2B%28x%29%29 Expand.
P+=+2%282x%2B6%29 Distribute the 2.
highlight%28P+=+4x%2B12%29