3.4 - 2.8d + 2.8d - 1.8

1.6

Step-by-step explanation:

Step 1:  Combine like terms

3.4 - 2.8d + 2.8d - 1.8

1.6 + 0d

1.6

 1.6

paula, cory, and krista

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