Because angleCBD+angleBDC+angleC=180
so angleCBD+angleBDC=180-angleC=180-82=98
because BC=DC
so angleCBD=angleBDC
so 2 angleCDB=98
so angleCDB=49
so y=29
by Joy Xu,紫馨雪汐
You can factor -80 as

So, we have

The square root of a product is the product of the square roots:

Since
and
, we have

Perimeter=4h+4
If the base is 2 more than the height, it gives us the equation:
b=h+2
The equation for the perimeter of a rectangle can be though of as 2b+2h, so substituting in (h+2) for b from the first equation, we get 2(h+2)+2h.
This can be simplified to be 2h+4+2h or 4h+4
(88 + 92 + 96 + x) / 4 = 90
(276 + x) / 4 = 90
276 + x = 90 * 4
276 + x = 360
x = 360 - 276
x = 84 <=== he would need an 84