Answer:

Step-by-step explanation:
We have,
Radius of the circle is 12 cm
Arc length, l = 21 cm
It is required to find the central angle of the circle. The formula for the length of an arc of a circle is :

is central angle

So, the angle at the centre of the circle is
.
Answer:
If Q=2.1(R)+5, then it would be 2.1(5)+5=15.5 ?
Step-by-step explanation: