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.

the circle graph is not a function.

step-by-step explanation:

the graph of the circle is not a function.

because for a graph to be a function, each value of x must give one value of y

in the circle, the values of x for -2< x< 2 each give 2 values of y.

hence this is not a function.

$25

step-by-step explanation:

25 - 4.50 = 20.5

20.5 / 2 = 10.25

10.25 + 10 = 20.25

20.25 - 12.50 = 7.75

therefore the answer is $25 as shown as the first number.