readyforgmat geometry problem
This topic has expert replies
-
- Legendary Member
- Posts: 576
- Joined: Sat Mar 13, 2010 8:31 pm
- Thanked: 97 times
- Followed by:1 members
Ans is B 30
since AB is equal to the radius of the circle triangle OAB is equilateral. hence angle AOB is 60
x=1/2*angle AOB=30
since AB is equal to the radius of the circle triangle OAB is equilateral. hence angle AOB is 60
x=1/2*angle AOB=30
"If you don't know where you are going, any road will get you there."
Lewis Carroll
Lewis Carroll
-
- Master | Next Rank: 500 Posts
- Posts: 154
- Joined: Thu Mar 19, 2009 12:55 pm
- Thanked: 5 times
- Followed by:1 members
I understand the equilateral part. But, how is x=1/2*angle AOB=30. Which property is this? Yes, the answer is Bliferocks wrote:Ans is B 30
since AB is equal to the radius of the circle triangle OAB is equilateral. hence angle AOB is 60
x=1/2*angle AOB=30
-
- Newbie | Next Rank: 10 Posts
- Posts: 5
- Joined: Thu Mar 25, 2010 4:50 am
Here, the AB is equal to the Radius. So if we draw a triangle with AB as the base and the third vertex as the centre O, we get a triangle AOB. Now Angle x and Angle AOB is made by the same base AB.
Now we know angle at the centre of the circle is twice the angle at the circumference.
or, angle AOB = 2* angle x
Now, triangle AOB is equilateral.
60 = 2*x
or, x=30
Thus B
Now we know angle at the centre of the circle is twice the angle at the circumference.
or, angle AOB = 2* angle x
Now, triangle AOB is equilateral.
60 = 2*x
or, x=30
Thus B
-
- Master | Next Rank: 500 Posts
- Posts: 154
- Joined: Thu Mar 19, 2009 12:55 pm
- Thanked: 5 times
- Followed by:1 members
I still don't get the part about the angle at the center of the circle is twice the angle at the circumference. .I am doing math after 8 years..I want to know the theory ..I know that inscribed angle of a diameter is 90 degrees.Nilakshi1001 wrote:Here, the AB is equal to the Radius. So if we draw a triangle with AB as the base and the third vertex as the centre O, we get a triangle AOB. Now Angle x and Angle AOB is made by the same base AB.
Now we know angle at the centre of the circle is twice the angle at the circumference.
or, angle AOB = 2* angle x
Now, triangle AOB is equilateral.
60 = 2*x
or, x=30
Thus B
-
- Legendary Member
- Posts: 576
- Joined: Sat Mar 13, 2010 8:31 pm
- Thanked: 97 times
- Followed by:1 members
this is the theory behind 'the angle at the center of the circle is twice the angle at the circumference'.Let me know if it clarifies the questions.
here angle AOB=2(x+y)=angle ACB
here angle AOB=2(x+y)=angle ACB
Last edited by liferocks on Tue Apr 27, 2010 10:45 pm, edited 1 time in total.
"If you don't know where you are going, any road will get you there."
Lewis Carroll
Lewis Carroll