Vertically opposite angles
Name: _____________________ Date: __________
Show your thinking with numbers, words, or a drawing.
1. Two straight lines cross. Find the angle marked with a question mark. The diagram is not drawn to scale.
2. Two straight lines cross. Find the angle marked with a question mark. The diagram is not drawn to scale.
3. Two straight lines cross. Find the angle marked with a question mark. The diagram is not drawn to scale.
4. Two straight lines cross. Find the angle marked with a question mark. The diagram is not drawn to scale.
5. Two straight lines cross. Find the angle marked with a question mark. The diagram is not drawn to scale.
Answer key · Vertically opposite angles
1. 40
The ? is vertically opposite the 40° angle: they sit across from each other where the lines cross.
Vertically opposite angles are equal.
So the angle is 40°.
2. 155
The ? is vertically opposite the 155° angle: they sit across from each other where the lines cross.
Vertically opposite angles are equal.
So the angle is 155°.
3. 125
The ? is vertically opposite the 125° angle: they sit across from each other where the lines cross.
Vertically opposite angles are equal.
So the angle is 125°.
4. 135
The ? is vertically opposite the 135° angle: they sit across from each other where the lines cross.
Vertically opposite angles are equal.
So the angle is 135°.
5. 65
The ? is vertically opposite the 65° angle: they sit across from each other where the lines cross.
Vertically opposite angles are equal.
So the angle is 65°.
Try it together
Choose a question from the printable. Use objects or a drawing to show your thinking, then explain your method to someone at home.