Which set of the side lenths form a right triangle?

Step-by-step explanation:

If for x ≤ y < z

x² + y² = z²

then x, y and z form a right triangle.

1 .

15m, 20m, 25m

15² + 20² = 225 + 400 = 625

25² = 625

CORRECT :)

2.

3ft, 6ft, 5ft

3² + 5² = 9 + 25 = 34

6² = 36

34 ≠ 36

3.

10in, 41in, 40in

10² + 40² = 100 + 1600 = 1700

41² = 1681

1700 ≠ 1681

4.

7cm, 8cm, 10cm

7² + 8² = 49 + 64 = 113

10² = 100

113 ≠ 100

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation: