P=2 (l+w)
P= 2 (80 + 1151)
P= 2 (1231)
P= 2462
The given known values are: Length of 4 cm Width is unknown Perimeter is 34 cm Find the dimensions of the rectangle. Since the geometric formula for perimeter is:
P= 2 (l + w)
L = 2w – 4 cm
W =?
Derivation and solution:
34 = 2 (2w - 4) + 2w
34 = 4w – 8 + 2w
42 = 6w 42/6 = w
W = 7 cm
34 = 2l + 2(7)
34 = 2l + 14
2l = 34 – 14
2l = 20
L = 20/2
L = 10 cm