Mathematics for IGCSE & O level - Circle Theorems (Section 2)
1
What is the property of angle subtended at the center by an arc?
Trả lời
(C)
It is twice the angle at the circumference subtended by the same arc.
2
What relationship exists between opposite angles of a cyclic quadrilateral?
Trả lời
(B)
They are supplementary.
3
What is the relationship between the lengths of the tangents drawn from an external point to a circle?
Trả lời
(A)
They are equal.
4
In a circle, a chord is drawn. A line is drawn from the center of the circle perpendicular to the chord. What can be said about the chord and the line?
Trả lời
(A)
The line bisects the chord and forms a right angle.
5
If a circle has a radius of 5 cm, and a chord is drawn 3 cm from the center, what is the length of the chord?
Trả lời
(C)
8 cm
6
In a cyclic quadrilateral, angles A and C are opposite angles. If angle A = 75 degrees, what is the measure of angle C?
Trả lời
(B)
105 degrees
7
In a circle with center O, chords AB and CD intersect at point E inside the circle. Which of the following are true statements regarding the angles formed?
Trả lời
A
C
D
8
What is the relationship between the lengths of the tangents from an external point to a circle?
Trả lời
(A)
Equal
9
What type of angle is formed in a semicircle?
Trả lời
(C)
A right angle
10
Which of the following statements about angles in circles are correct?
Trả lời
A
C
11
What angle is formed by a tangent and a radius at the point of tangency?
Trả lời
(C)
90 degrees
12
In a circle, a chord forms an angle at the centre of 100°. What is the angle subtended by the same chord at the circumference?
Trả lời
(C)
50°
13
If two tangents from a point P are drawn to a circle with center O, and angle between the tangents is 60 degrees, what is the angle between the tangents and the radii at the point of contact?
Trả lời
(C)
90 degrees
14
Which of the following is a key characteristic of a cyclic quadrilateral?
Trả lời
(C)
Opposite angles are supplementary.
15
Which of the following is the converse of the theorem stating 'Equal chords are equidistant from the center'?
Trả lời
(A)
Chords equidistant from the center are equal.
16
What relationship exists between the angles marked with letters in the circles?
Trả lời
A
B
C
17
What type of angle is inscribed in a semicircle?
Trả lời
(C)
Right
18
If two tangents are drawn from a point outside a circle, what is always true about their lengths?
Trả lời
(C)
They are equal in length.
19
Which property relates to the lengths of tangents drawn from a point outside the circle?
Trả lời
(A)
They are equal.
20
If two circles touch externally, how many common tangents can be drawn?
Trả lời
(C)
3
21
How does the angle at the center of a circle, subtended by an arc, relate to the angle at the circumference subtended by the same arc?
Trả lời
(C)
The angle at the center is twice the angle at the circumference.
22
If a tangent touches a circle at point P and the radius is OP, what is the angle between them?
Trả lời
(C)
90°
23
Two tangents are drawn from an external point to a circle. What is true about the lengths of these tangents?
Trả lời
(B)
They are equal in length.
24
Which statement correctly describes the property of angles in the same segment of a circle?
Trả lời
(C)
They are equal.
25
If a chord of a circle subtends an angle of 70 degrees at the center, what angle does it subtend at any point on the major arc?
Trả lời
(A)
35 degrees
26
In a circle, if two chords are the same length, how are they positioned relative to the center?
Trả lời
(A)
They are equidistant from the center.
27
If two angles in the same segment of a circle are subtended by the same arc, how are these angles related?
Trả lời
(C)
They are equal.
28
What is the relationship between the angles in the same segment of a circle?
Trả lời
(C)
They are equal.
29
What can be determined about the quadrilateral formed by two radii and two tangents from an external point to a circle?
Trả lời
(C)
It's always a kite.
30
Which of the following must be true in a circle?
Trả lời
A
B
C
31
What is the relationship between the angle at the center of a circle and the angle at the circumference subtended by the same arc?
Trả lời
(B)
The angle at the center is twice the angle at the circumference.
32
What is the relationship between a tangent to a circle and the radius drawn to the point of contact?
Trả lời
(B)
They are perpendicular.
33
What can you deduce about the chords which are equidistant from the centre of a circle?
Trả lời
(A)
The chords are of equal length.
34
If a line segment from the center of a circle bisects a chord (but isn't a radius), what's the relationship between the line segment and the chord?
Trả lời
(B)
They are perpendicular.
35
What can be concluded if two circles touch externally?
Trả lời
(C)
The distance between their centers is the sum of their radii.
36
What can you say about the triangles formed when two tangents intersect at a point outside the circle, where the radii meet the tangents?
Trả lời
(B)
They are congruent.
37
What is the necessary and sufficient condition for a quadrilateral to be cyclic?
Trả lời
(A)
Its opposite angles are supplementary.
38
What is the correct relationship between an angle formed by two intersecting chords inside a circle and the arcs they intercept?
Trả lời
(C)
The angle is half the sum of intercepted arcs.
39
In a circle, if a chord is drawn to the circle, which of the following is correct?
Trả lời
(A)
The perpendicular from the centre to the chord bisects the chord.
40
In the context of circle theorems, which of the following is a correct statement regarding alternate segment theorem?
Trả lời
(A)
The angle between a tangent and a chord is equal to the angle in the opposite segment.
41
In a circle, which relationships can be used to find angle measures?
Trả lời
A
B
C
D
42
If a quadrilateral is inscribed in a circle, what must be true about its opposite angles?
Trả lời
(C)
They are supplementary.
43
If a line segment is drawn from the center of a circle to the midpoint of a chord, what is the relationship between that line segment and the chord?
Trả lời
(B)
It is perpendicular to the chord.
44
Which of the following statements is true about the angles in the same segment of a circle?
Trả lời
(C)
They are equal.
45
Given a circle, what is the relationship between an angle formed by two tangents at the external point and the angle formed at the centre by the radius that meets the tangent?
Trả lời
(C)
They are complementary.
46
Which of the following can be used to determine the length of a chord?
Trả lời
A
B
C
D
47
In a cyclic quadrilateral, if one of the angles is 70 degrees, what is the measure of the opposite angle?
Trả lời
(C)
110 degrees
48
Which properties must be true in a cyclic quadrilateral?
Trả lời
(B)
Opposite angles must add up to 180 degrees.
49
What is the relationship between tangents drawn from an external point to a circle?
Trả lời
(C)
They are equal in length.
50
In a circle, if two chords are equal in length, what can you conclude about their distance from the center?
