SEAGReady
Shape and SpaceP7 level24 questions in the full course

Angles in QuadrilateralsSEAG Practice Questions

Understanding that angles in a quadrilateral add up to 360° and using this to find missing angles.

Where your child meets this in real life: Understanding angles in picture frames, tiles, or building plans

What your child needs to know

SEAGReady breaks angles in quadrilaterals into 3 steps, taught in order so each skill builds on the last.

  1. 1

    One Missing Angle

    Find a missing angle in a quadrilateral when three angles are given

  2. 2

    Using Right Angles

    Find missing angles when some angles are right angles or described as equal

  3. 3

    Special Quadrilaterals

    Find missing angles using properties of rectangles, parallelograms, and other special quadrilaterals

Try these SEAG-style questions

Three free sample questions from our angles in quadrilaterals course. Every question comes with a full explanation, and hints that guide without giving the answer away.

Question 1Confidence builder

The quadrilateral shown has angles of 80°, 95°, 110°, and one unknown angle. What is the missing angle?

A quadrilateral with three interior angles labelled 80, 95, and 110 degrees and the fourth angle marked with a question mark.
Answer choices for question 1
Question 2Confidence builder

The quadrilateral shown has two right angles and another angle of 80°. What is the fourth angle?

A quadrilateral with two corners marked 90 degrees, another angle labelled 80 degrees, and the fourth angle marked with a question mark.
Answer choices for question 2
Question 3Confidence builder

In a parallelogram, one angle is 65°. What is the angle next to it (adjacent angle)?

A parallelogram with parallel-side marks, one angle labelled 65 degrees, and its adjacent angle marked with a question mark.
Answer choices for question 3

Try the lesson: One Missing Angle

This is the exact interactive worked example your child sees in SEAGReady. Step through it and watch the method build up.

James is designing a kite for the school fair. The four corners of the kite have angles of 85 degrees, 90 degrees, 105 degrees, and one unknown angle.

What is the missing angle?

85° + 90° + 105° + x° = 360°

Add the known angles
1

Write down the three known angles: 85°, 90°, 105°

Step 1 of 4

Prefer to read? See every step written out

James is designing a kite for the school fair. The four corners of the kite have angles of 85 degrees, 90 degrees, 105 degrees, and one unknown angle.

What is the missing angle?

  1. 1

    Add the known angles

    • Write down the three known angles: 85°, 90°, 105°
    • Add them together85 + 90 + 105 = 280°
  2. 2

    Subtract from 360 degrees

    • Angles in a quadrilateral sum to 360°
    • Find the missing angle360 − 280 = 80°

The missing angle of the kite is 80°.

The key insight: All four angles in ANY quadrilateral always add up to 360 degrees!

Common mix-up: Using 180° instead of 360°. 180° is for triangles. Quadrilaterals have four angles that sum to 360°.

Mistakes to watch for

These are the misconceptions we see most often in angles in quadrilaterals, including the ones our practice questions are specifically designed to catch.

  • Using 180° instead of 360°
  • Not recognising when a shape is a quadrilateral
  • Errors with adding three angles then subtracting

Build these skills first

Struggling with angles in quadrilaterals? The real gap is often in one of these earlier topics.

Angles in TrianglesClassify Quadrilaterals

More shape and space practice

Name 2D ShapesLine Types and PropertiesDescribe Shape PropertiesClassify TrianglesUnderstand PolygonsLines of Symmetry
24 questions on this topic alone

Master angles in quadrilaterals and everything it unlocks

SEAGReady finds the exact step where your child gets stuck, teaches it with worked examples like the one above, and brings it back for review so it sticks.

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