Question

d uses 21 white tiles and some black tiles to make a mosaic. the mosaic has a total area of 144 square centimeters. each tile has an area of 3 square centimeters. how many black tiles did todd use? explain.

Explanation:

Step1: Find total number of tiles

The total area of the mosaic is 144 square centimeters and each tile has an area of 3 square centimeters. So the total number of tiles is total area divided by area per tile.
$$\text{Total number of tiles} = \frac{144}{3} = 48$$

Step2: Find number of black tiles

We know there are 21 white tiles. To find the number of black tiles, we subtract the number of white tiles from the total number of tiles.
$$\text{Number of black tiles} = 48 - 21 = 27$$

Answer:

Todd used 27 black tiles.