How do I solve this question?

Angle O is 72 degrees. Angle C is 18 degrees.

Step-by-step explanation:

You know that angle B is 90 degrees because Lines AC and OB are perperdicular at point B.

Add together all of the angles in the triangle

a + 4a + 90 = 180      Combine like terms

5a + 90 = 180

     - 90   - 90           Subtract 90 from both sides

5a = 90                     Divide both sides by 5

a = 18

Plug this answer into the angles to find their measures

Angle C = 18 degrees

Angle O = 4(18) = 72 degrees

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