The following figures are not drawn to scale but AB and CD (if present) are straight lines. Find x:

x = 60°

Step-by-step explanation:

From the figure and the fact that AB and CD are straight lines we can see that:

30° + 2x + ∠DOB = 180°    (eq. 1)

x + ∠DOB = 90°    (eq. 2)

Subtracting equation 2 to equation 1 we get:

30° + 2x + ∠DOB - (x + ∠DOB) = 180° - 90°

30° + x = 90°

x = 90° - 30°

x = 60°

step-by-step explanation:

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