An open box has external breadth 12 cm, length 15 cm and height 10 cm. If the thickness of the material of the box is 1 cm, calculate the total surface area of the box. (Hint; there are 14 surfaces).​

Answer 1

The external dimensions of the box are 15 cm by 12 cm by 10 cm.

If the thickness of the material is 1 cm, then the internal dimensions of the box are (15 - 2) cm by (12 - 2) cm by (10 - 2) cm.

The surface area of the bottom of the box is 15 cm * 12 cm = 180 cm^2.
The surface area of the top of the box is also 180 cm^2.
The surface area of the front of the box is (15 - 2) cm * (10 - 2) cm = 104 cm^2.
The surface area of the back of the box is also 104 cm^2.
The surface area of the left side of the box is (12 - 2) cm * (10 - 2) cm = 80 cm^2.
The surface area of the right side of the box is also 80 cm^2.

The total surface area of the box is 2 * (180 cm^2) + 2 * (104 cm^2) + 2 * (80 cm^2) = 628 cm^2. Answer: \boxed{628}.