Dmitri wants to cover the top and sides of this box with glass tiles that are 1 cm square. How many tiles will he need?
7 cm
14 cm
Dmitri will need
23 cm
glass tiles.

372

Step-by-step explanation:

We are given that the dimensions of the box are,

Length = 15 cm, Width = 20 cm and Height = 9 cm.

We know that the box represents a cuboid.

Since, surface area of a cuboid = L×W + 2×L×H + 2×W×H

Thus, the surface area of the box = 15×20 + 2×15×9 + 2×20×9

i.e. Surface area = 300 + 270 + 360

i.e. Surface area = 930.

Thus, the surface area of the box is 930 cm² i.e. 9300 mm².

Further, the sides of the tiles are 5 mm and the tile represents a square.

So, the surface area of the tile = 5 × 5 = 25 mm².

This gives us that,

Number of tiles required to cover the box =  = 372.

Hence, Dmitri requires 372 tiles to cover the box.

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step-by-step explanation: