Direction: In the Following Questions, A Statement of Assertion (A) Is...
Assertion: A wire is looped in the form of a circle of radius 28 cm. It is bent into a square. Then the area of the square is 1936 cm^2.
Reason: Angle described by a minute hand in 60 minutes = 360°.
Explanation:
To understand why the correct answer is option 'D', let's break down the problem into two parts:
Part 1: Wire looped in the form of a circle and bent into a square
- When a wire is looped in the form of a circle, the wire forms the circumference of the circle.
- The formula for the circumference of a circle is C = 2πr, where r is the radius of the circle.
- Given that the radius of the circle is 28 cm, the circumference of the circle would be C = 2π(28) = 56π cm.
- Now, when the wire is bent into a square, the length of the wire becomes equal to the perimeter of the square.
- The formula for the perimeter of a square is P = 4s, where s is the length of one side of the square.
- Therefore, 56π cm = 4s, which gives us s = 14π cm.
Part 2: Determining the area of the square
- The area of a square is given by the formula A = s^2, where s is the length of one side of the square.
- Substituting the value of s from Part 1, we get A = (14π)^2 = 196π^2 cm^2.
- Now, if we approximate the value of π to be 3.14, the area of the square would be approximately 1936 cm^2 (196 * 3.14^2).
- Therefore, the area of the square is 1936 cm^2.
Conclusion:
The assertion that the area of the square formed by bending the wire into a square is 1936 cm^2 is true. However, the reason given about the angle described by a minute hand in 60 minutes being 360° is irrelevant and does not provide any explanation for the assertion. Hence, the reason is false. Therefore, the correct answer is option 'D' - Assertion (A) is false but reason (R) is true.
Direction: In the Following Questions, A Statement of Assertion (A) Is...
Assertion (A) is false but reason (R) is true.
We have,
2π r = length of wire
2 x 22/7 x 28 = length of wire
length of wire = 176cm
Now, perimeter of square = 176
4a = 176
a = 44
Area of square = (44)2 = 1936 cm2
The minute hand moves 360 degrees in 60 minute(or 6 degrees in one minute) and hour hand moves 360 degrees in 12 hours(or 0.5 degrees in 1 minute).