Answer:
b = sqrt(45)
Explanation:
This is a right triangle, so we can use the Pythagorean theorem
a^2 + b^2 = c^2 where a and be are the legs and c is the hypotenuse
2^2 + b^2 = 7^2
4 + b^2 = 49
Subtract 4 from each side
b^2 = 49-4
b^2 = 45
Take the square root of each side
sqrt(b^2) = sqrt(45)
b = sqrt(45)