Answer:
A: 5 CM
B: 2.5 CM
C: ABC approx. equal to EDC (I'm not 100% sure on this one, but it makes most sense.)
I can't help you with number four, I'm sorry. I hope someone else comes along and helps with that!
Explanation:
The symbol being used means "approximate equality" meaning that the two angels are alike. So in A, the two sides on the shapes are both 5 cm. On B, since it is half of that side, it would be half of five, making it 2.5 cm. For C, the middle letter is the one touched second. Therefore when you draw the shape it makes the most sense that it's ABC approx. equal to EDC. Not to mention that ABC and the next angel has to match, so since the C is last, it also matches in that spectrum.
For D, I don't know the terminology, I'm sorry.