The common ratio of the sequence is r the sequence is (42, 21, 10.5, 5.25, . . .)

Step-by-step explanation:

r = 21/42 = 1/2  ( also 10.5 / 21 = 1/2)

This is a Geometric Sequence with first term 42 and common ratio 1/2.

Step-by-step explanation:

A protractor is a handheld to use in measuring angles. It is most cases made up of plastic or glass materials, and can accurately measure angles of circles up to 180°.

However, when measuring straight lengths, a ruler or tape has better measuring accuracy than the protector.