Alex needs 80
cm
80 cm80, start text, space, c, m, end text of thread for a sewing project. The thread is on a spool with a circumference of
10
cm
10 cm10, start text, space, c, m, end text.
How many times must Alex unwind the spool to get the length of thread he needs?

  8 full turns

Step-by-step explanation:

80 cm is 8 times 10 cm, so is 8 times around the spool.

Alex must unwind 8 full turns of thread from the spool.

__

He must unwind it once.

answer: 75°

step-by-step explanation:

∠esk is the supplement of ∠edk, so is 100°. ∠esd = 1/2·arc ed, so is 25°.

since ∠esk = ∠esd + ∠dsk

you have 100° = 25° + ∠dsk . .

fill in known values 75° = ∠dsk . . . . .

subtract 25°

step-by-step explanation:

the answer is b.

64

step-by-step explanation:

c=2πr=2·π·8≈64