Answer:
AB = 2*sqrt(5) or
AB = 4.47
Step-by-step explanation:
AB is the hypotenuse of a right triangle A and B and the corner where 2 and 4 meet.
The length of AB is governed by the Pythagorean Theorem.
AB^2 = x^2 + y^2 Substitute 2 and 4 for x and y
AB^2 = 2^2 + 4^2 Expand the right side
AB^2 = 4 + 16 Add the right side
AB^2 = 20 Take the square root of both sides
sqrt(AB^2) = sqrt(20)
Factor 20 = 2*2 *5
Rule: when taking the square root of a number the pairs can take 1 member of the pair outside the root sign and throw the other one a way.
AB = 2 * sqrt(5) One of the roots has been thrown away.
