1. To estimate, lets round the dimensions to 14 feet and 12 feet. Then, we calculate the perimeter as usual.
(14 + 12)2 = 26 * 2 = 52 feet as an estimate.
2. We need to write 8 and 3 inches in feet, and to do that we divide by 12, giving us 2/3 and 1/4. So, the mixed numbers are 13 2/3 feet and 12 1/4 feet. Each fraction represents the inches.
3. Using the fractions, we can find the perimeter.
(13 2/3 + 12 1/4)2 = 25 11/12 * 2 = 51 10/12 = 51 5/6 feet.
4. Our result from part 3 is pretty close to our estimate from part 1 - just 1/6 feet, or 2 inches off.
5. Now, we can just subtract the width of the doorway from our perimeter.
51 5/6 - 2 1/4 = 49 7/12 feet.
6. Finally, we divide our new perimeter by 8, and then round up.
49 7/12 / 8 ≈ 7 boards.
