Question

Plz help what is the measure of AC ?

Answer 1

D.) 30°

Explanation:

I am really hoping you mean angle AC:

If you have a 90° angle in a triangle (like the one created by ACB), the other two angles in the triangle have to add up to 90°. This is because a triangles angles will always add up to 180°. If you already have a 90° angle:

150° is wrong because 150°+90°=240, not a triangle measure

120° is wrong because 120°+90°=210, not a triangle measure

90° is wrong because 90°+90°=180°, but this is only two angles, not three

30° is correct because 30°+90°=120°, less than 180°, leaving room for a third angle.