Step 1: Identify the properties of △AOC.
OA and OC are radii of the circle. Therefore, OA=OC.
This means △AOC is an isosceles triangle.
Step 2: Determine the base angles of △AOC.
In an isosceles triangle, the angles opposite the equal sides are equal.
Given ∠OAC=20∘.
Since OA=OC, then ∠OCA=∠OAC.
∠OCA=20∘
Step 3: Calculate x using the sum of angles in a triangle.
The sum of angles in any triangle is 180∘.
In △AOC:
∠AOC+∠OAC+∠OCA=180∘
Substitute the known values:
x+20∘+20∘=180∘
x+40∘=180∘
x=180∘−40∘
x=140∘
x=140∘
That's 2 down. 3 left today — send the next one.