a chord of a circel is equal to the radius of the circel . find the angel subtended by the chord at a point on the minor arc. fig also see plz
Answers
Step-by-step explanation:
Given:-
Achord of a circel is equal to the radius of the circle.
To find :-
Find the angel subtended by the chord at a point on the minor arc.
Solution:-
( See the above attachment)
Let O is the centre of the circle .
AB is the Chord .
AB=Radius of the circle.
C is the point in the minor arc.
D is the point in the major arc
Angle subtended by the chord at C in the minor arc = angle ACB
Angle subtended by the chord at D in the major arc = angle ADB
On joining OA and OB we get ∆OAB in which
OA = OB = AB = radius
=>all the three sides are equal.
=>∆OAB is an equilateral triangle
= Each angle is equal to 60°
angle AOB = angle OAB = angle OBA = 60°
major arc ADB makes an angle ADB
we know that
"angle subtended by an arc at the centre is double angke subtended by at any other point on it".
=>angle AOB = 2( angle ADB)
= 60° =2 (angle ADB)
=>angle ADB = 60°/2
= angle ADB = 30°
and
all the vertices A,B,C,D are lie on the same circle.
=>ABCD is a cyclic quadrilateral
We know that
The sum of opposite angles is 180°
=>angle ADB +angle ACB = 180°
=>30°+angle ACB = 180°
=>angle ACB = 180°-30°
angle ACB = 150°
Answer:-
Angle subtended by the arc at the point in minor arc = 150°
and in the major arc = 30°
Used formulae:-
- "angle subtended by an arc at the centre is double angke subtended by at any other point on it".
- The sum of opposite angles is 180°
Step-by-step explanation:
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