What is the OA?
I got the answer: 40
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Circle and Arcs
Source: Beat The GMAT — Problem Solving |
What is the OA?
I got the answer: 40
Because, the arc AXB is 2/9th of the total arch.
The angle for the full circle is 360 degree, so if we draw an angle from the center (O) connecting A and B, the measurement of angle AOB would be 360*(2/9) = 80 degree.
As a formula: the angle BCA is half of AOB.
So, BCA = 40.
Is it?
I got the answer: 40
Because, the arc AXB is 2/9th of the total arch.
The angle for the full circle is 360 degree, so if we draw an angle from the center (O) connecting A and B, the measurement of angle AOB would be 360*(2/9) = 80 degree.
As a formula: the angle BCA is half of AOB.
So, BCA = 40.
Is it?
I also got 40, but this way:
The arcs ratio is 1:2:6 (BZC:AXB:AYC) so the angles opposing each of them also have the same ratio 1:2:6
1:2:6 sum 9
x:y:z 180 degrees
y= 180 *2 /9 = 40
The arcs ratio is 1:2:6 (BZC:AXB:AYC) so the angles opposing each of them also have the same ratio 1:2:6
1:2:6 sum 9
x:y:z 180 degrees
y= 180 *2 /9 = 40
x + y + z = 360 degrees
x = 2z ; y = 3x
x + 3x + x/2 = 360; 9x/2 = 360; x = 80 which is Angle (AOB); So A(ACB) = 80/2 = 40
x = 2z ; y = 3x
x + 3x + x/2 = 360; 9x/2 = 360; x = 80 which is Angle (AOB); So A(ACB) = 80/2 = 40
If you cant explain it simply you dont understand it well enough!!!
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