Chelsea is making a kite in the shape of a triangle. To determine if the triangle is a right triangle, Chelsea completed the following steps. Step 1:
Find the side lengths of the triangle: 30 inches, 24 inches, 18 inches.

Step 2:
Substitute the values into the Pythagorean theorem: 18 squared + 24 squared = 30 squared.

Step 3:
Combine like terms: (18 + 24) squared = 30 squared.

Step 4:
Evaluate each side: 1764 not-equals 900.

Chelsea says the triangle is not a right triangle. Which best describes the accuracy of her explanation?