Let the height of the original pyramid be represented by h. Then the cut off top has a height of (h -2). The scale factor for the area is the square of the scale factor for height, so we have ...

(height ratio)^2 = 1/2

((h -2)/h)^2 = 1/2

(h -2)√2 = h . . . . . . square root; multiply by h√2

h(√2 -1) = 2√2 . . . . add 2√2 -h

h = (2√2)/(√2 -1) ≈ 6.8284 . . . units

The altitude of the original pyramid is about 6.83 units.

7 0

2 years ago

I have this for my math review & i just don't seem to get it...<br>what is (.9x+.8y)^2

elena55 [62]

Can you take the quantity [ x + y ] and square it ?

Can you take the quantity [ x + 2y ] and square it ?

Then you should have no trouble with the square of (.9x + .8y) .

The square of any binomial (expression with 2 terms) is

(square of the first term)
+ (square of the second term)
+ 2 times (product of the terms) .

8 0

3 years ago