The circumference of a circle is 78π cm. Find the diameter, the radius, and the length of an arc of 140°.
A. 156 cm; 39 cm; 160π cm
B. 39 cm; 78 cm; 15.2π cm
C. 78 cm; 156 cm; 15.2π cm
D. 78 cm; 39 cm; 30.3π cm
The correct answer is the option D, which is: D. 78 cm; 39 cm; 30.3π cm The explanation is shown above: 1-The formula for calculate the circumference of a circle is: C=2πr 78π=2πr 2- The radius is: r=78π/2π r=39 cm 3- The diameter is: D=39 cm x 2 D=78 cm 4- The arc length is: arc length=(140°π/180°)(39 cm) arc length=30.3π cm
