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Which is false? Write the correct answer. For a right circular cylinder of base radius=7cm and height =14cm

A

curved surface area=`616cm^(2)`

B

Total surface area`=924cm^(2)`

C

Volume`=2156cm^(3)`

D

Totl area of the end face`=154cm^(2)`

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AI Generated Solution

The correct Answer is:
To solve the problem, we need to determine which statement about the right circular cylinder with a base radius of 7 cm and a height of 14 cm is false. We will calculate the curved surface area, total surface area, and volume of the cylinder, and then check the options provided. ### Step-by-Step Solution: 1. **Calculate the Curved Surface Area (CSA)**: The formula for the curved surface area of a right circular cylinder is given by: \[ \text{CSA} = 2 \pi r h \] Where: - \( r = 7 \, \text{cm} \) - \( h = 14 \, \text{cm} \) Substituting the values: \[ \text{CSA} = 2 \times \frac{22}{7} \times 7 \times 14 \] Simplifying: \[ \text{CSA} = 2 \times 22 \times 14 = 616 \, \text{cm}^2 \] 2. **Calculate the Total Surface Area (TSA)**: The formula for the total surface area of a right circular cylinder is: \[ \text{TSA} = 2 \pi r h + 2 \pi r^2 \] We already calculated \( 2 \pi r h = 616 \, \text{cm}^2 \). Now, we need to calculate \( 2 \pi r^2 \): \[ 2 \pi r^2 = 2 \times \frac{22}{7} \times (7)^2 = 2 \times \frac{22}{7} \times 49 \] Simplifying: \[ 2 \pi r^2 = 2 \times 22 \times 7 = 308 \, \text{cm}^2 \] Now, adding both areas: \[ \text{TSA} = 616 + 308 = 924 \, \text{cm}^2 \] 3. **Calculate the Volume (V)**: The formula for the volume of a right circular cylinder is: \[ V = \pi r^2 h \] Substituting the values: \[ V = \frac{22}{7} \times (7)^2 \times 14 \] Simplifying: \[ V = \frac{22}{7} \times 49 \times 14 = 22 \times 14 = 308 \times 7 = 2156 \, \text{cm}^3 \] 4. **Calculate the Area of the End Face**: The area of one end face of the cylinder is given by: \[ \text{Area of one end face} = \pi r^2 \] Substituting the values: \[ \text{Area of one end face} = \frac{22}{7} \times (7)^2 = \frac{22}{7} \times 49 = 154 \, \text{cm}^2 \] Therefore, the total area of both end faces is: \[ \text{Total area of end faces} = 2 \times 154 = 308 \, \text{cm}^2 \] ### Conclusion: After calculating all the values, we can summarize: - Curved Surface Area: \( 616 \, \text{cm}^2 \) (Correct) - Total Surface Area: \( 924 \, \text{cm}^2 \) (Correct) - Volume: \( 2156 \, \text{cm}^3 \) (Correct) - Total Area of End Faces: \( 308 \, \text{cm}^2 \) (Correct) If any option states that the total area of the end face is \( 154 \, \text{cm}^2 \), that would be false since the total area of both end faces is \( 308 \, \text{cm}^2 \).
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