A roll of tape has a circumference of 16.2 centimeters. The circumference decreases 2.8 centimeters after you use some of the tape. What is the diameter of the roll after you use the tape?

Answer 1

The original circumference was 16.2 cm, so after some tapes is used, the new circumference is 16.2-2.8=13.4cm

Now we just apply a formula that relates circumference to diameter. I'm sure you know that

C=πd

Plug in what we know:

13.4= π d

13.4/π=d Divide both sides by π

4.27cm (approx) = d Use calculator or an approximation of pi.

Best wishes

Answer 2

If circumference is π*d where d=diameter, by rearranging the equation, we see that diameter is C/π.

With this we can set up an equation:

(16.2-2.8)=π*x and solve for x

How did I set this up?

The left hand side represents the new circumference, and the right hand side multiplies the new diameter by π.

The new circumference after some of the tape is used is 13.4 cm. Divide this by π to find the diameter, and you get approx 4.27.

Answer 3

Divide the new circumference by π. That will give the new diameter in cm.

C = (16.2 - 2.8 ) cm

d = C/π

Plug in the numbers.