The given equation is:

1. Subtract 5 from both sides:

2. Divide both sides by 8:

3. Take the square root of both sides:
Answer:
d =13 cm
r = 6.5 cm
Step-by-step explanation:
The diameter is the distance across the circle, going through the center
d = 13 cm
The radius is 1/2 of the diameter
r = d/2 = 13/2 = 6.5 cm