Exercise 39 Page 739

Let's consider a circle with a radius of 6 cm and an arc with a measure of 60^(∘).

Since △ ABC is isosceles, by the Isosceles Triangle Theorem we get that m∠ A = m∠ B. Also, we have that m∠ C=60^(∘). Let's apply the Angle Sum Theorem.

Since the three angles of △ ABC have the same measure, it is an equilateral triangle. In consequence, AB=6 cm.

Next, if we triple the arc measure we will get an arc with a measure of 180^(∘), which implies the arc is a semicircle. Consequently, the corresponding chord is a diameter.

Then the length of AB is twice the radius — that is, AB=12 cm. As we can see, the length of the chord was not tripled. Thus, the answer to the question is no.