Solve the missing elements for each problem. use 3.14 for ~ | | . 1 ) s r t q radius: ______________ diameter: ______________ 4 inches circumference: ______________ area: ______________ 2 ) c b d a radius: ______________ diameter: ______________ 10 ft circumference: ______________ area: ______________ 3 ) r q s p radius: ______________ 18 yards diameter: ______________ circumference: ______________ area: ______________ 4 ) p o q n radius: ______________ diameter: ______________ 16 cm circumference: ______________ area: ______________ 5 ) e d f c radius: ______________ 19 mm diameter: ______________ circumference: ______________ area: ______________ 6 ) d c e b radius: ______________ 12 inches diameter: ______________ circumference: ______________ area: ______________ 7 ) j h k g radius: ______________ diameter: ______________ 28 ft circumference: ______________ area: ______________ 8 ) n m o l radius: ______________ 6 yards diameter: ______________ circumference: ______________ area: ______________ 9 ) h g j f radius: ______________ diameter: ______________ 18 cm circumference: ______________ area: ______________

we know that
diameter=radius*2
radius=diameter/2
area of circle=pi*r²
length of circumference=2*pi*r
so

Part 1) 4 inches circumference
4=2*pi*r--------> r=4/(2*pi)-----> r=2/pi-----> r=0.64 in
diameter=2*0.64-----> 1.28 in
area=pi*0.64²------> 1.29 in²

the answers Part 1) are
a) radius=0.64 in
b) diameter=1.28 in
c) area=1.29 in²

Part 2) 10 ft circumference
10=2*pi*r-----> r=10/(2*pi)----> r=5/pi-----> 1.59 ft
diameter=2*1.59------> 3.18 ft
area=pi*1.59²-----> 7.94 ft²

the answers Part 2) are
a) radius=1.59 ft
b) diameter=3.18 ft
c) area=7.94 ft²

Part 3) 18 yards diameter
radius=18/2-----> 9 yd
circumference=2*pi*9-----> 56.52 yd
area=pi*9²-----> 254.34 yd²

the answers part 3) are
radius=9 yd
circumference=56.52 yd
area=254.34 yd²

Part 4) 16 cm circumference
16=2*pi*r-----> r=16/(2*pi)----> r=8/pi-----> 2.55 cm
diameter=2*2.55------> 5.10 cm
area=pi*2.55²-----> 20.42 cm²

the answers Part 4) are
a) radius=2.55 cm
b) diameter=5.10 cm
c) area=20.42 cm²

Part 5) 19 mm diameter
radius=19/2-----> 9.5 mm
circumference=2*pi*9.5-----> 59.66 mm
area=pi*9.5²-----> 283.39 mm²

the answers part 5) are
radius=9.5 mm
circumference=59.66 mm
area=283.39 mm²

Part 6) 12 inches diameter
radius=12/2-----> 6 in
circumference=2*pi*6-----> 37.68 in
area=pi*6²-----> 113.04 in²

the answers part 6) are
radius=6 in
circumference=37.68 in
area=113.04 in²

Part 7) 28 ft circumference
28=2*pi*r-----> r=28/(2*pi)----> r=14/pi-----> 4.46 ft
diameter=2*4.46------> 8.92 ft
area=pi*4.46²-----> 62.46 ft²

the answers Part 7) are
a) radius=4.46 ft
b) diameter=8.92 ft
c) area=62.46 ft²

Part 8) 6 yards diameter
radius=6/2-----> 3 yd
circumference=2*pi*3-----> 18.84 yd
area=pi*3²-----> 28.26 yd²

the answers part 8) are
radius=3 yd
circumference=18.84 yd
area=28.26 yd²

Part 9) 18 cm circumference
18=2*pi*r-----> r=18/(2*pi)----> r=9/pi-----> 2.87 cm
diameter=2*2.87------> 5.74 cm
area=pi*2.87²-----> 25.86 cm²

the answers Part 9) are
a) radius=2.87 cm
b) diameter=5.74 cm
c) area=25.86 cm²