import math


def hypotenuse_length(leg_a, leg_b):
    """Find the length of a right triangle's hypotenuse

    :param leg_a: length of one leg of triangle
    :param leg_b: length of other leg of triangle
    :return: length of hypotenuse
    
    >>> hypotenuse_length(3, 4)
    5
    """
    return math.sqrt(leg_a**2 + leg_b**2)