Angles in a quadrilateral

Difficulty Standard · Set rixpyg

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1
Three angles of a quadrilateral are 70°, 55°, 45°. What is the fourth, in degrees?
2
Three angles of a quadrilateral are 65°, 20°, 55°. What is the fourth, in degrees?
3
Three angles of a quadrilateral are 55°, 80°, 100°. What is the fourth, in degrees?
4
Three angles of a quadrilateral are 50°, 65°, 35°. What is the fourth, in degrees?
5
Three angles of a quadrilateral are 80°, 70°, 35°. What is the fourth, in degrees?
6
Three angles of a quadrilateral are 45°, 75°, 30°. What is the fourth, in degrees?
7
Three angles of a quadrilateral are 85°, 45°, 40°. What is the fourth, in degrees?
8
Three angles of a quadrilateral are 30°, 50°, 75°. What is the fourth, in degrees?
9
Three angles of a quadrilateral are 50°, 35°, 40°. What is the fourth, in degrees?
10
Three angles of a quadrilateral are 55°, 50°, 55°. What is the fourth, in degrees?
11
Three angles of a quadrilateral are 80°, 65°, 40°. What is the fourth, in degrees?
12
Three angles of a quadrilateral are 50°, 50°, 70°. What is the fourth, in degrees?
13
Three angles of a quadrilateral are 25°, 25°, 130°. What is the fourth, in degrees?
14
Three angles of a quadrilateral are 80°, 30°, 110°. What is the fourth, in degrees?
15
Three angles of a quadrilateral are 70°, 65°, 40°. What is the fourth, in degrees?
16
Three angles of a quadrilateral are 30°, 60°, 90°. What is the fourth, in degrees?
17
Three angles of a quadrilateral are 55°, 35°, 70°. What is the fourth, in degrees?
18
Three angles of a quadrilateral are 25°, 80°, 60°. What is the fourth, in degrees?
19
Three angles of a quadrilateral are 80°, 40°, 80°. What is the fourth, in degrees?
20
Three angles of a quadrilateral are 55°, 20°, 75°. What is the fourth, in degrees?

What is in this set

The numbers in this set run from 20 to 130.
A careful solution takes 2 written steps on average.
The mistake this set invites most often, in 46% of the problems: the angles of a quadrilateral add to 360°, not 180°.
Answers are a whole number.

Drawing 240 problems from this page produced 235 different ones, 98% — so a sheet of 20 is a new sheet almost every time.

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.