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1 A 00-g box of cereal measures 20cın by 7cm by 31cm Find its surface area
A shoebox measures 30cm by 20cm by 12cm. Find the surface area of each box
Find the surface area of a cube whose lateral faces are bounded by length of 10 cm
4. What is the surface area of a sphere with a radius of 9 in?
cylinder has a diameter of 8 in and a height of 12 cm. Find the total surface area of the
Answers
Question :
A box of cereal measures 20 cm by 7cm by 31cm. Find its surface area.
Given :
- Length, Breadth and Height = 20cm, 7cm and 31cm.
To find :
- its surface area
Solution :
Surface Area = 2 (lb + lh + hb)
= 2 (20 × 7) + (20 × 31) + (31 × 7)
= 2 (140) + (620) + (217)
= 2 × 977
= 1954
Therefore, the surface area of the cereal box is 1954 cm².
Question :
A shoebox measures 30cm by 20cm by 12cm. Find the surface area of the shoe box.
Given :
- Length, Breadth and Height = 30cm, 20cm and 12cm.
To find :
- its surface area
Solution :
Surface Area = 2 (lb + lh + hb)
= 2 (30 × 20) + (30 × 12) + (12 × 20)
= 2 (600) + (360) + (240)
= 2 × 1200
= 2400
Therefore, the surface area of the shoebox is 2400 cm².
Question :
Find the surface area of a cube whose lateral faces are bounded by length of 10 cm.
Given :
- Lateral faces = 10 cm
To find :
- its surface area
Solution :
Surface area of a cube = 6a²
= 6 × 10²
= 6 × 100
= 600
Therefore, the Surface Area of the Cube is 600 cm².
Question :
What is the surface area of a sphere with a radius of 9 cm?
Given :
- Radius = 9 cm
To find :
- its surface area
Solution :
Surface area of Sphere = 4πr²
= 4 × 3.14 × 9²
= 4 × 3.14 × 81
= 12.56 × 81
= 1017.36
Therefore, the Surface Area of Sphere is 1017.36 cm².
Question :
A cylinder has a diameter of 8 cm in and a height of 12 cm. Find the total surface area of the cylinder.
Given :
- Diameter = 8 cm
- Height = 12 cm
To find :
- its total surface area
Solution :
Radius = 2 × r
8 cm = 8/2
= 4 cm
Total Surface Area of Cylinder = 2πr(h + r)
= 2 × 3.14 × 8 × (12 + 8)
= 6.28 × 8 × 20
= 50.24 × 20
= 1004.8
Therefore, the Total Surface Area of the Cylinder is 1004.8 cm².