10. In a cyclic quadrilateral, [tex]$\angle P$[/tex] and [tex]$\angle R$[/tex] are opposite angles.

a) Write the relation between [tex]$\angle P$[/tex] and [tex]$\angle R$[/tex]. (1)

b) Find the value of [tex]$x$[/tex], when [tex]$\angle P = 2x^{\circ}$[/tex] and [tex]$\angle R = 4x^{\circ}$[/tex]. (1)

c) Experimentally verify that the angle at the center of a circle is double the angle at its circumference standing on the same arc. (Two circles having at least 3 cm radii are necessary). (2)



Answer :

Sure, let's break down each part of the question step-by-step.

### a) Relation between ∠P and ∠R
In a cyclic quadrilateral, the opposite angles are supplementary. This means that their sum is 180°.

Therefore, the relation between ∠P and ∠R is:
[tex]\[ \angle P + \angle R = 180^\circ \][/tex]

### b) Find the value of [tex]\( x \)[/tex]
Given:
[tex]\[ \angle P = 2x^\circ \][/tex]
[tex]\[ \angle R = 4x^\circ \][/tex]

Since ∠P and ∠R are opposite angles in a cyclic quadrilateral, we have:
[tex]\[ 2x + 4x = 180^\circ \][/tex]

Combine like terms:
[tex]\[ 6x = 180^\circ \][/tex]

To solve for [tex]\( x \)[/tex]:
[tex]\[ x = \frac{180}{6} \][/tex]
[tex]\[ x = 30^\circ \][/tex]

### c) Experimentally verify the angle at the center is double the angle at the circumference standing on the same arc

For this part, you will need to conduct a practical experiment using two circles, each with a radius of at least 3 cm. Follow these steps:

1. Draw a Circle: Take a compass and draw a circle with a radius of at least 3 cm.
2. Mark an Arc: Choose any two points on the circumference of the circle; name them A and B.
3. Angle at the Circumference (∠APB): From point P on the circumference (different from points A and B), draw lines PA and PB to form the angle ∠APB.
4. Angle at the Center (∠AOB): Now, draw lines from the center of the circle O to points A and B to form the angle ∠AOB.
5. Measuring the Angles:
- Measure the angle ∠APB using a protractor.
- Measure the angle ∠AOB using a protractor.

You should find that:
[tex]\[ \angle AOB = 2 \times \angle APB \][/tex]

Repeat the procedure with the second circle to confirm your results. The experimental verification should show that the angle subtended at the center of a circle is indeed double the angle subtended at the circumference by the same arc, consistent with the theoretical principle.

This concludes the detailed step-by-step solution to the given question.