Which of the following statements is true?
OA. A 25° angle is congruent to a 25° angle.
OB. Two intersecting lines form two pairs of congruent angles.
OC. It is possible for congruent angles to add up to 90°.
OD. All of the above are true.

OD. All of the above

Step-by-step explanation:

a 25 degrees angle is the same, or congruent, to a 25 degrees angle. two intersecting lines are the same angle, therefore forming two pairs of congruent angles. congruent angles, for example a pair of two angles of 45 degrees, can add up to 90 degrees. since they are all true, its OD. All of the above are true.

94

step-by-step explanation:

average the numbers and use a variable to figure out the minimum to get a 90.

(79+94+91+92+x)/5=90

x = 94

(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