Question

Pierre cut the length of an 8 cm wide plank into nine pieces and arranged them as shown in the picture. The centrepiece is a square. How long was the original plank?

Answer 1

Answer: 200cm

Explanation:

The center Planck is a square of length 8cm.

The 4 next planks are of 16 cm each

And the next 4 Planks are of 32 cm each.

8 + 4(8×2) + 4(8×4)

8 + 4(16) + 4(32)

8 + 64 + 128

200 cm

Length of the original plank is 200cm