Help I know is easy but I don't know

? = 2 sqrt(21)

Step-by-step explanation:

We can use the Pythagorean theorem to solve since this is a right triangle

a^2 + b^2 =c^2

?^2 + 4^2 = 10 ^2

?^2 + 16 = 100

Subtract 16 from each side

?^2 +16-16 = 100-16

?^2 = 84

Take the square root of each side

sqrt(?^2) = sqrt(84)

? = sqrt(4) sqrt(21)

? = 2 sqrt(21)

Step-by-step explanation:

→You can use the Pythagorean Theorem:

→The "a," and "b," are the legs, and the "c," is the hypotenuse. In this case, we area already given the hypotenuse (10), and are solving for the leg. So plug in the numbers, like so:

→Subtract 16 from both sides:

→To get "b," by itself, square root both sides, like so:

it is b)

hope this : )

step-by-step explanation:

lockers 1, 4, 9, 16, 25, 40, and 49 are open

i ran through it by the other answer is wrong