The perimeter of the rectangle is 26 cm, length is 9 cm. What is the width and area?

The perimeter of the rectangle is P = 2 * (a + b), where a is the length of the rectangle, b is its width.
Therefore, knowing the perimeter and length of the rectangle, we can find its width.
P = 2 * (a + b),
P = 2 * a + 2 * b,
2 * b = P – 2 * a,
b = (P – 2 * a) / 2.
b = (26 – 2 * 9) / 2,
b = 8/2,
b = 4 (cm).
The area of the rectangle is:
S = a * b,
S = 9 * 4,
S = 36 (cm²).
Answer: b = 4 cm, S = 36 cm².