Label a box of cube shape with 15cm edge length. What's the area of the label;
15×15×4
=225×4
=900 square centimeters
If a ring has an inner diameter of 5cm and an outer radius of 9cm, what is the area of the ring in square centimeters?
9 × 9 × 3.14-5 × 5 × 3.14 = 175.84 square centimeter
The outer diameter of a ring is 10 cm, the inner diameter is 8 cm, and its area is () square centimeter
The outer diameter of a ring is 10 cm, the inner diameter is 8 cm, and its area is () square centimeter
π(10/2)^2-π(8/2)^2=9π