Stefan is measuring the angles of a triangle. he measures the first angle and gets a measure of 80° what does he know about the other two angles? a) they are each 50°. b) their measures should add up to be 100°. c) their measures should add up to be 280°. d) he doesn't know anything about the other two angles.

The answer is (B) Their measures should add up to be 100°.

We know that the sum of all angles of a triangle is equal to 180 degrees. Stefan has calculated the first angle and it came out to be 80 degrees. So the other two angles must be equal to 100 in order to complete the total measurement of triangle angles which is 180.

when rotating a figure 180 degrees, imagine that you are able to take the figure and turn it clockwise or counterclockwise around a center point. to rotate a figure 180 degrees, you will need to apply the rule (x, y) → (-x, -y). start by using a coordinate grid with coordinates for each vertex of the figure. the center point of the coordinate grid is located at (0, 0), which is what you will rotate the figure around. write down the original coordinates of the shape you are going to rotate. then, apply the rule. for example, coordinate (1, 2) becomes (-1, -2). another example would be, coordinate (-4, -2) becoming (4, 2). after you change each original coordinate to the rotated coordinate, you will draw your new figure.

step-by-step explanation: