Question

Before painting a picture on canvas, an artist must stretch the canvas on a rectangular wooden frame. To be sure the angles are true right angles, the artist can measure the diagonals of the stretched canvas. What should be the diagonal measure of a canvas whose sides are 55 inches and 1212 inches in length?

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Answer 1

9514 1404 393

Answer:

13 inches

Explanation:

The Pythagorean theorem can help. The square of the diagonal is the sum of the squares of the sides:

d^2 = 5^2 +12^2 = 25 +144 = 169

d = √169 = 13

The diagonal measure is 13 inches.

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Additional comment

The integer triple (5, 12, 13) is called a "Pythagorean triple." One of the more famous ones is (3, 4, 5). Another one commonly seen in Algebra problems is (7, 24, 25). It is worth noting these, as they show up often.