Write down the size of angle ABC give a reason for your answer

The angle of ABC is 90 degrees.

Using circle theorem,

The angle subtended by an arc at the centre is twice the angle subtended

at the circumference.

Therefore,

1 / 2 ∠O = ∠ABC

∠O = 180 (angle on a straight line)

Therefore,

∠ABC = 1 / 2 × 180

∠ABC = 180 / 2

∠ABC = 90°

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∠ ABC = 90°

Step-by-step explanation:

∠ ABC is the angle in a semi circle and is right, that is

∠ ABC = 90°

40 is the final : )

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