Match angles of rotation that have the same sine value.

Question

25°-----

130°----

−50°-------

205°-------

65°------

230*, 115*, 50*, 155, -130*, -25, -65*

Answer 1

None really.

Although there's some relations

sin25 = -sin205

sin(-50) = -sin130

sin130 = sin(2)(65)

Answer 2

Sketch yourself a unit circle. Remember that the sine refers to the y-coordinate of the point on the circle that has the given angle.

For example, looking at the 25° angle, an angle with the same y-coordinate would be a reflection over the y-axis, meaning it is 180° – 25° or 155°.

Looking at the 130° angle, find it on your unit circle. Reflect across the y-axis to get an angle of 50°. Those two angles have the same sine.

Keep in mind that angles from 0° to 180° will have sines will be 0 or else positive. Angles that are greater than 180 and less than 360° will have negative sines.