The rectangle is 13 cm wide and twice as long. Find the perimeter of this rectangle.

Since the width of the rectangle is thirteen cm, and the length is 2 times larger, then to find out the value of the length of the rectangle, you need to multiply the width of the rectangle by 2: 13 cm * 2 = 26 cm.The perimeter of the rectangle is equal to the sum of all its sides. Since the opposite sides of the rectangle are equal, then P = 2 * a + 2 * b. Substituting the known values of the sides, we get: P = 2 * a + 2 * b = 2 * 13 cm + 2 * 26 cm = 26 cm + 52 cm = 78 cm.
Answer: the perimeter of the rectangle is 78 cm.