To estimate the number of coins needed, divide the notebook’s side length by the coin’s diameter. Then, verify your estimate by physically measuring the notebook side and coin diameter, and placing the coins end-to-end to confirm the estimated number.
Step-by-step solution:
1. Estimate:
Measure the length of one side of the notebook using the 15-cm scale (let’s say the length is 20 cm).
Measure the diameter of the coin using the 15-cm scale (let’s say the diameter is 2 cm).
Divide the notebook length by the coin diameter: 20 cm / 2 cm = 10 coins. This is your initial estimate.
2. Verify:
Place the coins lengthwise, side-by-side along the measured notebook side, making sure there are no gaps.
Count the number of coins that fit.
If the number of coins you placed matches your initial estimate (10), your estimate is verified. If it’s slightly different, refine your estimate based on the actual placement of the coins.