Vertically opposite angles

Difficulty Standard · Set gz5nq4

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1
Two lines cross. One angle is 80°. What is the angle vertically opposite it, in degrees?
2
Two lines cross. One angle is 130°. What is the angle vertically opposite it, in degrees?
3
Two lines cross. One angle is 55°. What is the angle vertically opposite it, in degrees?
4
Two lines cross. One angle is 55°. What is the angle vertically opposite it, in degrees?
5
Two lines cross. One angle is 55°. What is the angle vertically opposite it, in degrees?
6
Two lines cross. One angle is 50°. What is the angle vertically opposite it, in degrees?
7
Two lines cross. One angle is 125°. What is the angle vertically opposite it, in degrees?
8
Two lines cross. One angle is 55°. What is the angle vertically opposite it, in degrees?
9
Two lines cross. One angle is 45°. What is the angle vertically opposite it, in degrees?
10
Two lines cross. One angle is 120°. What is the angle vertically opposite it, in degrees?
11
Two lines cross. One angle is 75°. What is the angle vertically opposite it, in degrees?
12
Two lines cross. One angle is 30°. What is the angle vertically opposite it, in degrees?
13
Two lines cross. One angle is 15°. What is the angle vertically opposite it, in degrees?
14
Two lines cross. One angle is 115°. What is the angle vertically opposite it, in degrees?
15
Two lines cross. One angle is 55°. What is the angle vertically opposite it, in degrees?
16
Two lines cross. One angle is 150°. What is the angle vertically opposite it, in degrees?
17
Two lines cross. One angle is 110°. What is the angle vertically opposite it, in degrees?
18
Two lines cross. One angle is 120°. What is the angle vertically opposite it, in degrees?
19
Two lines cross. One angle is 130°. What is the angle vertically opposite it, in degrees?
20
Two lines cross. One angle is 25°. What is the angle vertically opposite it, in degrees?

What is in this set

The numbers in this set run from 15 to 160.
A careful solution takes 1 written step on average.
The mistake this set invites most often, in 94% of the problems: that is the angle NEXT to it on the straight line; vertically opposite angles are equal.
Answers are a whole number.

Drawing 240 problems from this page produced 30 different ones, 13% — so a sheet of 20 will come back to a problem you have seen — there are only so many sensible ones of this kind.

The same skill, harder or easier

We would put this in front of a grade 6 class. That is our judgement, not a standard, and it is printed here so you can disagree with it. Everything else we put in that year.