The document proves that the alternate segment theorem, which states that any angle in an alternate segment of a circle is equal to an angle formed by the tangent and chord at the point of contact. It does this by joining a radius to the point of contact P and extending it to meet the circle at Z. It then uses properties of angles on tangents, in semicircles, and angle sums in triangles to show that ∠APY = ∠ABP.
2. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
3. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
A
B
O
X P
4. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
BPX PAB alternate segment theorem
A
B
O
X P
5. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
BPX PAB alternate segment theorem
Prove : APY ABP
A
B
O
X P Y
6. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
BPX PAB alternate segment theorem
Z Prove : APY ABP
A Proof: Join PO and produce to meet the
B circumference at Z
O
X P Y
7. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
BPX PAB alternate segment theorem
Z Prove : APY ABP
A Proof: Join PO and produce to meet the
B circumference at Z
O
Join AZ
X P Y
8. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
BPX PAB alternate segment theorem
Z Prove : APY ABP
A Proof: Join PO and produce to meet the
B circumference at Z
O
Join AZ
ZPY 90 radius tangent
X P Y
9. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
BPX PAB alternate segment theorem
Z Prove : APY ABP
A Proof: Join PO and produce to meet the
B circumference at Z
O
Join AZ
ZPY 90 radius tangent
X P Y APZ 90 - APY
10. Alternate Segment
Theorem
(9) An angle formed by a tangent to a circle with a chord drawn to the
point of contact is equal to any angle in the alternate segment.
BPX PAB alternate segment theorem
Z Prove : APY ABP
A Proof: Join PO and produce to meet the
B circumference at Z
O
Join AZ
ZPY 90 radius tangent
X P Y APZ 90 - APY
PAZ 90 in semicircle
12. Z
A
B
O
X Y
P
PAZ AZP APZ 180 sum APZ
13. Z
A
B
O
X Y
P
PAZ AZP APZ 180 sum APZ
90 AZP 90 APY 180
14. Z
A
B
O
X Y
P
PAZ AZP APZ 180 sum APZ
90 AZP 90 APY 180
AZP APY
15. Z
A
B
O
X Y
P
PAZ AZP APZ 180 sum APZ
90 AZP 90 APY 180
AZP APY
AZP ABP 's in same segment =
16. Z
A
B
O
X Y
P
PAZ AZP APZ 180 sum APZ
90 AZP 90 APY 180
AZP APY
AZP ABP 's in same segment =
APY ABP
17. Z
A
B
O
X Y
P
PAZ AZP APZ 180 sum APZ
90 AZP 90 APY 180
AZP APY
AZP ABP 's in same segment =
APY ABP
Exercise 9F; 2ace etc, 3bd, 4bd, 5b, 7b, 9b, 10b, 12, 14, 15b