Answer:
1. 2x+5
2. 20x-8y
3.2a+2b+3b+sqrt(2)
Step-by-step explanation:
1. 2/5x+1 is one side, and it's a regular pentagon, so it's 5(2/5x+1). 5(2/5x+1)=2x+5, so the perimeter is 2x+5.
2.due to all the angles of the cross the same, they must be right angles, and because of this, we can assume that the cross can be made a square with the same length and width, and that the extra part is equivalent to the sides, so we can do 8(5/2x-y). 8(5/2x-y)=20x-8y, which means 20x-8y is the answer.
3. due to the congruent sides, we know this right triangle is a 45 45 90 triangle, which means we know that the hypotenuse of triangle a is 3b/2, and furthermore triangle a is also a 45 45 90 triangle so its legs are (3b/2)*sqrt(2). when adding all the sides together, we get 2((2a-b)/2)+2(3b/2)+2(3b/2*sqrt(2)) =2a-b+3b+3b*sqrt(2)=2a+2b+3b+sqrt(2), thus the answer is 2a+2b+3b+sqrt(2).
