Use the Pythagorean Theorem: a^2 + b^2 = c^2
a and b are the measures of the legs and c is the measure of the hypotenuse
Let's solve for a (the length of the other leg)
I am hoping that m is not a variable and just an abbreviation for meters
b = 4 m
c = 6 m
a^2 + 4^2 = 6^2
a^2 + 16 = 36
a^2 = 20
a = \(\sqrt{20}\)
after simplifying...
a = \(2 \sqrt{5}\) m