You have to first mess around with the first shape, ABCD, and split that into a rectangle and a right triangle. once you do that, it's pretty painstaking, but simple.
if you look at it you can tell that EFGH is just half the size, but the same ratios and everything.
So, you would just take every perimeter measurement from ABCD, and divide it by two and then sum them together.
2.5 + 1.5 + 4.0 + 2.0 = 10
Answer:
4845 combinations
Step-by-step explanation:
Whenever there is a selection of some elements from a certain group, there are several ways to do so. There are different combinations from the group which can be selected. The concept of combination means that there are certain number of elements to be selected from the group and there is no importance given to the order of the selection. The total number of students are 20, and 4 out of them have to be selected. It can be clearly seen that the order of selection does not matter, therefore the formula to be used is:
Combinations = 20C4 = (20*19*18*17)/(4*3*2*1) = 4845.
So the correct answer is 4845 combinations!!!