Math word problem???
I want to buy a sleeve for my cell phone that protects all surfaces of my prize possesion. the width of my cell phone is 5cm. less than the length. The height of my cell phone is 8 cm. If the total surface area is 124 cm, than what is it length, width, and height in cm?
Hint: Total surface area= 2lw+2lh+2wh
Comments
The formula you have is SA= 2lw+2lh+2wh
Using SA =124, w=L-5, h=8, plug into the formula:
124= 2(L)(L-5)+2(L)(8)+2(L-5)(8)
124= 2(L^2)-10L+16L+16L-80
0= 2L^2+22L-204
0= L^2+11L-102
0=(L+17)(L-6)=0
L cannot be negative, so L =6cm
w= 6-5=1 cm
Then H= 8cm
Hoping this helps!
L-5=w
L
h=8
2l*(l-5)+2*l*8+2*(l-5)*8=124
L=6
W=1
H=8