Angles in a quadrilateral

Difficulty Starter · Set qf39hw

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1
Three angles of a quadrilateral are 50°, 80°, 40°. What is the fourth, in degrees?
2
Three angles of a quadrilateral are 40°, 20°, 130°. What is the fourth, in degrees?
3
Three angles of a quadrilateral are 40°, 60°, 80°. What is the fourth, in degrees?
4
Three angles of a quadrilateral are 70°, 30°, 20°. What is the fourth, in degrees?
5
Three angles of a quadrilateral are 60°, 50°, 80°. What is the fourth, in degrees?
6
Three angles of a quadrilateral are 40°, 100°, 40°. What is the fourth, in degrees?
7
Three angles of a quadrilateral are 80°, 40°, 90°. What is the fourth, in degrees?
8
Three angles of a quadrilateral are 60°, 70°, 80°. What is the fourth, in degrees?
9
Three angles of a quadrilateral are 50°, 50°, 20°. What is the fourth, in degrees?
10
Three angles of a quadrilateral are 80°, 30°, 70°. What is the fourth, in degrees?
11
Three angles of a quadrilateral are 40°, 100°, 70°. What is the fourth, in degrees?
12
Three angles of a quadrilateral are 50°, 30°, 30°. What is the fourth, in degrees?
13
Three angles of a quadrilateral are 70°, 50°, 70°. What is the fourth, in degrees?
14
Three angles of a quadrilateral are 60°, 60°, 70°. What is the fourth, in degrees?
15
Three angles of a quadrilateral are 50°, 80°, 40°. What is the fourth, in degrees?
16
Three angles of a quadrilateral are 30°, 80°, 80°. What is the fourth, in degrees?
17
Three angles of a quadrilateral are 50°, 70°, 50°. What is the fourth, in degrees?
18
Three angles of a quadrilateral are 30°, 90°, 70°. What is the fourth, in degrees?
19
Three angles of a quadrilateral are 70°, 90°, 50°. What is the fourth, in degrees?
20
Three angles of a quadrilateral are 50°, 40°, 100°. 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 40% 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 192 different ones, 80% — 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.