Mathematics for IGCSE & O level - Circle Theorems (Section 1)
1
In a circle, if two chords are equidistant from the center, what can be said about the length of those chords?
คำตอบ
(A)
They are equal.
2
What is the relationship between a tangent and a radius of a circle at the point of tangency?
คำตอบ
(B)
They are perpendicular.
3
If an arc subtends an angle of 70 degrees at the center, what angle does it subtend at a point on the major arc?
คำตอบ
(A)
35 degrees
4
What can you say about the perpendicular from the centre of a circle to a chord?
คำตอบ
(C)
It bisects the chord and is perpendicular.
5
What is the sum of opposite angles in a cyclic quadrilateral?
คำตอบ
(B)
180 degrees
6
If two circles touch internally, how many common tangents can be drawn?
คำตอบ
(B)
2
7
If a line drawn from the center of a circle bisects a chord, what does that line do to the chord?
คำตอบ
(C)
It's perpendicular to the chord.
8
If a tangent and a secant are drawn from an external point to a circle, how are they related?
คำตอบ
(D)
They intersect the circle at different points.
9
If two chords of a circle are equal, what can you deduce about their distances from the center?
คำตอบ
(A)
They are equal.
10
What is the sum of the interior angles of a cyclic quadrilateral?
คำตอบ
(C)
360 degrees
11
What is the length of a chord that is 8 cm from the center of a circle with a radius of 10 cm?
คำตอบ
(C)
16 cm
12
The angle between a tangent and a radius drawn to the point of contact is always:
คำตอบ
(D)
90 degrees
13
Two equal chords AB and CD intersect at P inside the circle. What can you deduce about angles formed?
คำตอบ
C
D
14
In a cyclic quadrilateral ABCD, angle A is 80 degrees. What is the size of angle C?
คำตอบ
(B)
100 degrees
15
If a line from the center of a circle bisects a chord, what angle does it create with the chord?
คำตอบ
(D)
90 degrees
16
In the alternate segment theorem, what angle is equal to the angle between a tangent and a chord?
คำตอบ
(B)
The angle in the alternate segment
17
Which of the following is NOT a property of cyclic quadrilaterals?
คำตอบ
(D)
All sides are equal.
18
If two circles touch externally, how many common tangents can be drawn?
คำตอบ
(C)
3
19
What is the relationship between the angle formed by a tangent and a chord at the point of contact and the angle in the alternate segment?
คำตอบ
(C)
They are equal.
20
What is the relationship between two tangents drawn from an external point to a circle?
คำตอบ
(B)
They have the same length.
21
Two equal chords AB and CD of a circle intersect at a point P inside the circle. Which is correct?
คำตอบ
A
B
22
What is the angle between a tangent and a radius drawn to the point of contact?
คำตอบ
(C)
90 degrees
23
Which statement accurately reflects the angle properties of a semi-circle?
คำตอบ
(B)
The angle is always 90 degrees.
24
If a chord is 10 cm long and is 12 cm from the center of the circle, what is the radius of the circle?
คำตอบ
(B)
10 cm
25
What can you say about the chords in a circle that are equidistant from the center?
คำตอบ
(B)
They are equal in length.
26
If a chord of length 8 cm is 3 cm away from the center of a circle, what is the radius of the circle?
คำตอบ
(B)
5 cm
27
What is always true about the angle between a tangent and a radius at the point of contact?
คำตอบ
(C)
90 degrees
28
What is the angle between a chord and a tangent at the point of contact equal to?
คำตอบ
(A)
Angle in the alternate segment
29
A tangent to a circle meets the radius at what angle?
คำตอบ
(D)
90 degrees
30
Which theorem is most useful in determining the angles formed by a chord and a tangent at the point of contact?
คำตอบ
(B)
Alternate Segment Theorem
31
What theorem relates the angle formed by a tangent and a chord with an angle in the alternate segment of the circle?
คำตอบ
(C)
Alternate Segment Theorem.
32
Which geometric relationships are involved when determining the angles in a diagram with a circle and a tangent?
คำตอบ
A
B
33
If a chord of a circle subtends an angle of 120 degrees at the center, what is the angle subtended by the same chord at a point on the major arc?
คำตอบ
(B)
60°
34
If a chord subtends an angle of 60 degrees at the center of a circle, what is the angle it subtends at the circumference?
คำตอบ
(C)
30 degrees
35
Which of the following statements are true regarding a tangent and a chord in a circle?
คำตอบ
A
C
36
If two chords intersect inside a circle, how are the angles formed related to the intercepted arcs?
คำตอบ
(A)
Each angle equals half the sum of the intercepted arcs.
37
What is the measure of an angle inscribed in a semicircle?
คำตอบ
(D)
90°
38
If two chords are equidistant from the center of a circle, which is true about their lengths?
คำตอบ
(A)
They are equal.
39
How many common tangents can be drawn to two circles that do not intersect?
คำตอบ
(D)
4
40
In a circle, the angle in a semi-circle is always:
คำตอบ
(D)
90 degrees
41
What does the perpendicular bisector of a chord pass through?
คำตอบ
(B)
The center of the circle
42
In a cyclic quadrilateral, what is the sum of any two opposite interior angles?
คำตอบ
(B)
180 degrees
43
In a cyclic quadrilateral, angle A is 110 degrees. What is the measure of its opposite angle C?
คำตอบ
(A)
70 degrees
44
What is the name of the theorem that states the angle in a semicircle is a right angle?
คำตอบ
(C)
Angle in a Semicircle Theorem
45
If a line from the center of a circle meets a chord at right angles, what does it do to the chord?
คำตอบ
(A)
It bisects the chord.
46
Which of the following theorems is illustrated by the statement: "The angle between a tangent and a chord equals one angle made by their chord in the alternate segment of the circle"?
คำตอบ
(D)
The alternate segment theorem.
47
What is true about opposite angles in a cyclic quadrilateral?
คำตอบ
(B)
They are supplementary.
48
If a chord makes an angle of 40° at the circumference of a circle, what angle does it make at the center?
คำตอบ
(C)
80°
49
What's the relationship between opposite angles in a cyclic quadrilateral?
คำตอบ
(B)
They're supplementary.
50
Which statements are accurate about the properties of circle theorems?
