Answer:
1 inch
Step-by-step explanation:
If we call the thickness of the frame x, then the dimensions of the glass are:
w = 8 − 2x
h = 10 − 2x
The area of the glass is width times height:
48 = (8 − 2x) (10 − 2x)
Distribute and simplify:
48 = 80 − 16x − 20x + 4x²
0 = 4x² − 36x + 32
0 = x² − 9x + 8
Factor and solve:
0 = (x − 1) (x − 8)
x = 1 or x = 8
x can't be more than 4 (half the width of the frame), so x = 1 inch.
