Area and Circumference of Circles

= + + + Area and Circumference of Circles Circumference (C) - distance around a circle (similar to perimeter) If you measure the circumference and divide it by the diameter, the answer will always equal or 3.14... Diameter Diameter + Diameter + Diameter = + Circumference 3.14 diameters equal circumference

Formula for circumference: C = d or C = 2 r Find the circumference of each circle using the formula. Calculator permitted. Show required steps. Use 3.14 for . 1.) 5.1 m 2.) 8 cm

4.) Formula for circumference: C = d or C = 2 r 3.) Find the circumference of each circle using the formula. Show required steps. Leave your answer in terms of . 14 cm 3.) 4.) 35 m

Area A= r2 π≈3.14 A = A = A = 3 m How many square units are in the circle? Use 3.14 for pi. Required Steps 
(Calculator permitted) A = 3 m A = A =

5 m 2.) 7 m Find the area of each circle. Show all required steps. 1.) (use 3.14 for pi) 2.) (write your answer in terms of ) 5 m 7 m

Find the area of each circle when the diameter is given. First find the radius, then show required steps. 3.)(use 3.14 for pi) 4.) d = 9 ft. 12 m (write your answer in terms of )

Circles and Irregular Figures Find the area of the shaded region. 1.) 2.) 14 ft 20 ft (use 3.14 for pi) 16 m

Finding the radius or diameter given the area 1.) The circular floor of the Pantheon in Rome has an area 
of about 1473 square meters. What is the diameter of 
the floor to the nearest tenth of a meter? 2.) The area of a circle is 615 cm2, what is the radius (round your answer to the nearest whole number)?

. 1.) 2.) Demonstrate Understanding 8 m 11 cm Find the area and circumference for each. Use 3.14 for 1.) 2.) 11 cm 8 m 15 mm . 15 mm 3.) The area of a circle is 254 m2, what is the radius?