Final answer:
To find the perimeter of the shaded shape, add the lengths of the two semicircles and the straight line segment between them.
Step-by-step explanation:
To find the perimeter of the shaded shape, we need to find the lengths of the two semicircles and the straight line segment between them. The circumference of a circle is given by the formula C = πd, where d is the diameter. So the circumference of the semicircle with a diameter of 12 cm is C = π12 cm = 12π cm. Similarly, the circumference of the semicircle with a diameter of 20 cm is C = π20 cm = 20π cm. The straight line segment between the two semicircles is the sum of their diameters, which is 12 cm + 20 cm = 32 cm. Therefore, the perimeter of the shaded shape is 12π cm + 20π cm + 32 cm.