To solve the questions related to the properties of quadrilaterals inscribed in a circle, we can apply key properties such as the fact that the opposite angles of a quadrilateral that is inscribed in a circle sum to 180°, as well as relationships between angles and arcs.
Question 1
Given:
- m∠QUAD = 55°
- m∠AUAD = 112°
- m∠UAD = 100°
To find m∠AD, we use the property that the opposite angles of a cyclic quadrilateral sum to 180°:
m∠QUAD + m∠AD = 180° m∠AD = 180° - m∠QUAD m∠AD = 180° - 55° = 125°
Therefore, m∠AD = 125°.
Question 2
We know:
- m∠B = 4y + 27
- m∠D = y - 12
Since ABCD is cyclic, opposite angles sum to 180°:
m∠B + m∠D = 180° 4y + 27 + (y - 12) = 180 5y + 15 = 180 5y = 165 y = 33
Now substitute y back into m∠D:
m∠D = y - 12 = 33 - 12 = 21°
Therefore, m∠D = 21°.
Question 3
Given the two consecutive angles of a cyclic quadrilateral:
- First angle = 88°
- Second angle = 108°
Let the angle opposite the 108° angle be labeled as x°.
Using the property that opposite angles sum to 180°:
x + 108° = 180° x = 180° - 108° x = 72°
Thus, x = 72°.
Question 4
Similar to question 3:
Given:
- First angle = 108°
- Second angle = 88° Let the angle opposite 88° be labeled y°.
Using the property that opposite angles sum to 180°:
y + 88° = 180° y = 180° - 88° y = 92°
Therefore, y = 92°.
Question 5
We are given:
- Arc AT = 50°
- Arc TH = 170°
- m∠AMTH = 54°
To find m∠A, we use the relationship between the angle formed by two chords and the measure of the arc they intercept. The measure of angle A will be half the measure of the arc that it intercepts.
The arc intercepted by angle A (arc AT) is the arc opposite to angle MATH, which consists of the total arc minus the arc MA and arc TH:
The arc opposite M (the angle we know) would be arc TH + arc AT:
Arc opposite A = 50° + 170° = 220°.
Now to find m∠A:
m∠A = (arc opposite A) / 2 = (220°) / 2 = 110°.
Thus, m∠A = 110°.