Two circles are shown in the diagram.

Circles C 1 and C 2 are shown. The diameter of circle 1 is 1. The diameter of circle 2 is 2 r.

Since all circles are similar, a proportion can be set up using the circumference and diameter of each circle. Substitute the values d1 = 1, C1 = π, and d2 = 2r into the proportion.

StartFraction C 1 Over d 1 EndFraction = StartFraction C 2 Over d 2 EndFraction

Which shows how to correctly solve for C2, the circumference of any circle with radius r?

15 points ! ~ see if you know the answer to both you!

Factor -8x3-2x2-12x-3 by grouping what is the resulting expression?

Martha has a deck of cards. she has lost some of the cards, and now the deck only contains nine spades, eleven diamonds, eight clubs, and twelve hearts. martha predicts that whenever she draws a card from the deck without looking, she will draw a club one-fifth of the time. which activity would best allow martha to test her prediction? a. randomly draw a card from the box and see if it is a club. b. randomly draw a card. then, continue to draw another card until all eight clubs are drawn. c. randomly draw and replace a card 120 times. then, observe how close to 30 times a club is drawn. d. randomly draw and replace a card 100 times. then, observe how close to 20 times a club is drawn.