Answer:
The length of the rectangle is 9 cm
Step-by-step explanation:
Given: The length of rectangle(l) = (x+3) cm and a width of rectangle (w) = [tex]\frac{1}{2} x[/tex] cm a
Also, perimeter of rectangle is 24 cm.
Perimeter of rectangle is to add the lengths of all the four sides.
Perimeter of rectangle (P) is given by;
P=2(l+w)
Substituting the value of P = 24 cm , l = (x+3) cm and w =[tex]\frac{1}{2} x[/tex]
then,
[tex]24 = 2 (x+3+\frac{1}{2} x)[/tex]
Divide by 2 both sides of an equation;
[tex]12 = x+3+\frac{1}{2}x[/tex]
Combine like terms;
[tex]12 =\frac{3x}{2} +3[/tex]
Subtract 3 from both the sides we get;
[tex]12-3 = \frac{3x}{2} +3-3[/tex]
Simplify:
[tex]9 =\frac{3x}{2}[/tex]
Multiply both sides by [tex]\frac{2}{3}[/tex] we get
[tex]x = 9 \times \frac{2}{3} = 3 \times 2 = 6[/tex]
Therefore, length of rectangle(l) = (x+3) = 6+3 = 9 cm