Answer:
9cm
Step-by-step explanation:
Perimeter of a rectangle = 2(L+W)
L is the length = x+3 cm
W is the width = 1/2 x cm
Perimeter = 24cm
Substitute into the equation;
P = 2(x+3+ 1/2 x)
P = 2(3/2x + 3)
24 = 2(3x/2 + 3)
Expand
24 = 3x + 6
3x = 24 - 6
3x = 18
x = 18/3
x = 6
Since L = x+3
L = 6+3
L = 9cm
Hence the length of the rectangle is 9cm