Puan Hasnah menyusun enam alas gelas yang sama saiz dalam satu garis lurus di tengah permukaan meja bulat. Jejari permukaan meja ialah 36 cm. Hitung luas bahagian meja itu yang tidak ditutup dengan alas gelas. (Guna [tex]\(\pi = 3.142\)[/tex])

Puan Hasnah arranged six coasters of the same size in a straight line at the center of a circular table top. The radius of the table top is 36 cm. Calculate the area that is not covered by the coasters. (Use [tex]\(\pi = 3.142\)[/tex])



Answer :

Sure, let's break down the problem step-by-step to find the uncovered area of the table.

1. Calculate the Area of the Table Top:
- The radius of the table top is given as 36 cm.
- The formula for the area of a circle is [tex]\( A = \pi r^2 \)[/tex].
- Using [tex]\(\pi = 3.142\)[/tex] and [tex]\(r = 36\)[/tex] cm, the area of the table top is:
[tex]\[ A_{\text{table}} = 3.142 \times (36)^2 = 4072.032 \text{ cm}^2 \][/tex]

2. Determine the Radius of Each Coaster:
- Six coasters fit in a straight line across the diameter of the table.
- Hence, the diameter of the circle formed by the six coasters is equal to the diameter of the table.
- The diameter of the table is [tex]\(2 \times 36 \text{ cm} = 72 \text{ cm}\)[/tex].
- Therefore, the diameter of each coaster is [tex]\( \frac{72 \text{ cm}}{6} = 12 \text{ cm}\)[/tex].
- The radius of each coaster is [tex]\( \frac{12 \text{ cm}}{2} = 6 \text{ cm}\)[/tex].

3. Calculate the Area of One Coaster:
- Using the radius of one coaster which is 6 cm, and the same formula for the area of a circle:
[tex]\[ A_{\text{coaster}} = 3.142 \times (6)^2 = 113.112 \text{ cm}^2 \][/tex]

4. Calculate the Total Area Covered by Six Coasters:
- Since there are six coasters, the total area covered by the coasters is:
[tex]\[ A_{\text{total coasters}} = 6 \times 113.112 = 678.672 \text{ cm}^2 \][/tex]

5. Calculate the Uncovered Area:
- The area of the table top that is not covered by the coasters is:
[tex]\[ A_{\text{uncovered}} = A_{\text{table}} - A_{\text{total coasters}} \][/tex]
[tex]\[ A_{\text{uncovered}} = 4072.032 - 678.672 = 3393.360 \text{ cm}^2 \][/tex]

Thus, the area of the table that is not covered by the coasters is approximately [tex]\( 3393.36 \text{ cm}^2 \)[/tex].