100 likes | 211 Views
6.7 Circumference & Arc Length. Circumference. Defn . – the distance around a circle. Thm. 6.19 – Circumference of a Circle – C = 2 r or C = d * Always use the button on your calculator, NOT 3.14!!!. C = d C = (12) C = 12 C = 37.70 cm. C = 2 r C = 2(6) C = 12
E N D
Circumference • Defn. – the distance around a circle. • Thm. 6.19 – Circumference of a Circle – C = 2r or C = d * Always use the button on your calculator, NOT 3.14!!!
C = d C = (12) C = 12 C = 37.70 cm C = 2r C = 2(6) C = 12 C = 37.70 cm * If asked to leave your answer in terms of , the result would look like this. Ex: Find the circumference of a circle with a diameter of 12 cm. (Round to 2 decimal places.) OR cm
C = 2r 52 = 2r 52/2 = r 8.28 in. r C = d 52 = d 52/ = d 16.55 in. d So, r 16.55/2 r 8.28 in. Ex: Find the radius of a circle with a circumference of 52 in. OR
Arc Length • Defn. – a portion of the circumference of a circle. • The measure of an arc is in degrees. • The length of an arc is in linear units. (such as ft, cm, etc.)
Arc Length Corollary ( • The length of AB is: (
Ex: Find the length of JK. ( ( C 60o 16 in. J K
Arc Length Corollary Observations • The length of a semicircle is ½ the circumference. • The length of a 90o arc is ¼ the circumference. 180o 90o
Ex: Find the m LM. ( ( ( 16.76 in. ( L M 8 in. ( C ( (
Ex: Find the circumference of circle C. ( R ( 10.2 cm S 45o C