#1
That is false..one could have side lengths of 9 and 1, and the other could have side lengths of 3. Both the areas would be 9, but the figures would not be congruent.
#2
That is true, they must both have the same side length to have the same perimeter, therefore they will also have the same area.
4 + 10 = 2 x 2 + 2 x 5 = 2 x (2 + 5)
Answer:
25% decrease
Step-by-step explanation:
Take the original amount of books and subtract the new number of books
20 -15 = 5
Divide by the original amount of books
5/20 = .25
Multiply by 100%
25%
It is a decrease since the amount went down
25% decrease