Final answer:
The circumference of a disc with a radius of 3.5 cm is approximately 22.0 cm, using the formula C = 2πr and rounding to two significant figures.
Step-by-step explanation:
To calculate the circumference of a disc with a radius of 3.5 cm, we use the formula C = 2πr where 'C' represents the circumference, 'π' is approximately 3.14159, and 'r' is the radius of the disc. Plugging in the radius of 3.5 cm:
C = 2 * 3.14159 * 3.5 cm
C = 2 * 3.14159 * 3.5 cm = 21.99115 cm
Therefore, the circumference of the disc is approximately 22.0 cm, rounding to two significant figures as the original value of the radius was given to two significant figures.