Page 8 - Lesson note 5 Angle subtended by arc Ch.- 10 Circle
P. 8
Solution:
BAC = 50⁰and DBC = 70⁰ (given)
From figure:
BDC = BAC = 50⁰ [Angle on same segment]
In ΔBDC: Using angle sum property, we have
BDC+ BCD+ DBC=180⁰
Substituting given values, we get
50⁰ + x+ 70⁰ = 180⁰
0
x= 180⁰−50⁰−70 =60⁰
or x = 60⁰.
(iv)
Solution:
BAC = 35⁰ and DBC = 65⁰
From figure:
BDC = BAC = 35⁰ [Angle in same segment]
In ΔBCD:
Angle sum property, we have
BDC + BCD + DBC = 180⁰
35⁰ + x + 65⁰ = 180⁰
0
0
0
0
or x = 180 – 35 – 65 = 80
Question 5: O is the circumcentre of the triangle ABC and OD is perpendicular on BC.
Prove that BOD = A.
Solution:
