Question 1157991: Drawn in a circle whose radius is 12 cm, chord AB is 16 cm long. Calculate the angular
size of minor arc AB. Found 2 solutions by mananth, MathTherapy:Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Perpendicular to chord from centre bisects chord
AD=BD=8
Triangle AOD right triangle
By Pythagoras theorem
12^2= 8^2+OD^2
OD = 4sqrt(5)
tan B = 4sqrt(5)/8 = 1.12
Angle B = 48.2 ~48 deg
In triangle AOD
angle A +angle AOD +angle ODA =180 deg
48+90+AOD =180
Angle AOD =42 deg
Angle AOC = 2* 42 =84
84 is central angle
Measure of arc AC =84 degrees
With center O, and altitude OD drawn from center to chord, we get cos ∡OAD =
∡OBD also = 48.19o
Therefore, central ∡AOB = 180 - 2(48.19o) = 180 - 96.38o = 83.62o
From this, we can see that
That's ALL!!