this is grade 10 math questions

a rectangular window is 5 feet 3 inches in length, and 3 feet 6 inches in width. if the perimeter of the window must have caulking that costs 32cents per inch, how much will the caulking cost??
the answer is $67.20
but i got 846.73 :(
what i did was

5ft=60inch legth= 60 + 3 = 63inches
and for the width
3ft=36inches width= 36 +6 = 42inches

42 x 63 =2646

2646 x 0.32= 846.72
plzz tell me what i did wrong

2 answers

You found the area, not the perimeter.

P = 2L + 2W
perimeter=2*5feet3inch + 2*3feet6inch
=17feet6inch (1feet=12inch)
total inches = 17*12+6
= 210 inches
210*0.32=67.20