Given d = {x | x is a whole number}. e = {x | x is a perfect square between 49 and 100}. f = {x | x is an even number between 10 and 20}. 1.the expression d∪f means (64 and 81) or (all whole numbers). 2.the expression d∩f means (16,22,24,18) or (12,14,16,18). 3.the expression d∩e means (all whole numbers) or (64,81). 4.the expression e∩f means (all whole numbers) or (empty set). 5.the expression d∩(e∪f) means (empty set) or (81,64,12,14,16,18)

i can you, i love poetry

mean, 40.6

step-by-step explanation:

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240