Write an addition equation or a subtraction equation (your choice!) to describe the diagram.​

(-9) + (-2) = -11

Step-by-step explanation:

The first arrow on the number line starts from 0, moves downwards 9 units from 0.

We would write this as -9.

Also, the next arrow starts moves from -9, 2 units downwards.

We would write this as -2

The addition equation would be:

(-9) + (-2) = -11

step-by-step explanation :

we know that

the measurement of the outer angle is the semi-difference of the arcs which comprises

in this problem

m< xzy is the outer angle

substitute the values

the measure of angle xoy is equal to

> by central angle

substitute the value