Final answer:
To find the circumference of a dinner plate with a radius of 3.5 inches, you multiply 2π by the radius (2πr), giving an approximate circumference of 22 inches when rounded to two significant figures.
Step-by-step explanation:
The dinner plate at your grandma's house has a radius of 3.5 inches.
To find the circumference of the dinner plate, we use the formula C = 2πr, where C is the circumference and r is the radius of the circle. Plugging in the given radius:
C = 2π(3.5 inches)
C = 7π inches
Using the approximation π ≈ 3.14159, we can calculate the circumference:
C ≈ 7 × 3.14159 inches
C ≈ 21.99153 inches
Therefore, the approximate circumference of the dinner plate is 22 inches, rounded to two significant figures since 3.5 has only two significant figures.