7. CHALLENGE: Use the digits 0 to 9 to make the equation true. You don't need to use all thedigits you can only use each digit once. 20 = ___+(___-___)×___​

20=4+(2-2)×5

Step-by-step explanation:

Simple :-)

i leave the calculator work to you.

7. diameter 4 miles, circumference 4π miles

8. radius 0.2 miles, circumference 0.4π miles

[this is a bad problem because the actual radius of a car on the track is less than 0.2 miles so the answer is less than 0.4π miles]

9. radius 6 feet, circumference 12π feet

10. diameter 14 cm, circumference 14π cm

11. diameter 4.8 feet, circumference 4.8π feet