Which of the following statements is/are true? A: In a circle, PQ is a chord and OP and OQ are the radii of the circle. If ∠POQ = 90°, then ratio of the area of triangle POQ and that of circle will be 7: 22. B: Area of a circle is one-fourth of the product of ‘π’ and square of diameter of circle. C: Diameter of a semi-circle is 38(8/9)% of its perimeter.
Which of the following statements is/are true? A: In a circle, PQ is a chord and OP and OQ are the radii of the circle. If ∠POQ = 90°, then ratio of the area of triangle POQ and that of circle will be 7: 22. B: Area of a circle is one-fourth of the product of ‘π’ and square of diameter of circle. C: Diameter of a semi-circle is 38(8/9)% of its perimeter. Correct Answer Only B and C
GIVEN:
Three statements.
CONCEPT:
Properties of chord, radius and area of circle.
FORMULA USED:
Area of triangle = (1/2) × Base × Height
Perimeter of semi-circle = (πr + 2r)
CALCULATION:
A: Let the radius of the circle OP = OQ = r.
Given, ∠POQ = 90°, So the area of triangle POQ will be (1/2) × OP × OQ = r2/2.
The area of the circle = πr2 = (22/7)r2.
Now the ratio of the area of triangle POQ and that of circle = (r2/2): (22/7)r2 = 7: 44.
B: Let diameter of a circle is ‘D’, then its radius (r) = ‘D/2’.
So, area of the circle = πr2 = πD2/4.
C: Let radius of a semicircle be ‘r’, then its diameter will be ‘2r’ and its perimeter will be (πr + 2r) = = 36r/7.
The diameter of semicircle is × 100 = 38(8/9)% of its perimeter.
∴, only B and C are TRUE.