Based on the equation 18^2 + b^2 = 30^2, we can determine that the triangle is a right-angled triangle and b is the length of the hypotenuse. This is because the Pythagorean theorem states that in a right-angled triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the other two sides. In this case, b is the hypotenuse and 18 and 30 are the other two sides.
