Answer:
Ideas that the author most wants readers to know.
Explanation:
Since this is an informational text, the key ideas would be what the author most wants readers to know.
There are shapes which are cut into sections and would be made into a larger shape if they were fitted together. One good example of this would be a half circle and another half circle; because if they were joined together, they would be a full circle.
With this in mind, there are different forms through which smaller shapes can be fitted together to become a larger shape and they could be a half trapezium, etc.
Please note that your question is incomplete so I gave you a general overview so that you could have a better understanding of the concept.
Read more about shapes here:
brainly.com/question/25965491