Samuel needs 2 boards to make a shelf. One board is 84 centimeters long and the other is 45 centimeters long.

What is the total length of the shelf?

centimeters

What would your answer be in millimeters?

millimeters

Answer: 129 cm = 1290 mm

Step-by-step explanation:

Hi, to answer this question we simply have to add the length of both boards.

Mathematically speaking:

Total length = 84 cm + 45 cm = 129 centimiters

Since:

1 cm = 10mm

To convert 129 cm to mm we have to multiply it by 10.

129 cm x 10 mm/cm = 1290 mm

Feel free to ask for more if needed or if you did not understand something.

The length of the shelf is 129 cm or 1290 mm.

Step-by-step explanation:

Since Samuel will use the two boards to make the shelf, then the total length of the shelf is the sum of the lengths of each board. So in order to solve this problem we must do as shown bellow:

length shelf = length board1 + length board2

length shelf = 84 + 45 = 129 cm

In order to convert this to milimeters we must multiply the answer above by 10. So we have:

length shelf = 129*10 = 1290 mm

The length of the shelf is 129 cm or 1290 mm.