Final answer:
The shape made by two semicircles with diameters of 12cm and 20cm can be found using the circumference formula for semicircles.
Step-by-step explanation:
To find the shape made by two semicircles with diameters of 12cm and 20cm, we need to first understand what a semicircle is. A semicircle is half of a circle, and it is formed when a straight line divides a full circle into two equal halves.
The formula to find the circumference of a full circle is C = πd, where C is the circumference and d is the diameter. Since a semicircle is half of a full circle, we can use the same formula to find the circumference of a semicircle.
For the semicircle with a diameter of 12cm, the circumference would be C = π(12) = 12π cm. For the semicircle with a diameter of 20cm, the circumference would be C = π(20) = 20π cm.