Angle relationships – Grade 7 math lesson

Lesson 12 of 21 in the Grade 7 math course

US version. US grades, US spelling and dollars ($). · UK Maths Department

A complete 45-minute lesson for grade 7 (ages 12–13) that runs on this page – at school or at home. Every answer is graded right away, with a worked explanation.

Time: 45 minutes + 20 min homework
Grade: Grade 7 (ages 12–13)
You need: Paper, a pencil and this page
Graded: Instantly, with explanations

For parents: how to use this lesson

You don't need to know this topic yourself. The lesson explains each step on screen, one tidy step at a time. Every answer is graded straight away with a worked explanation, so you never have to grade anything.

Read what your child will learn and the big ideas together.
Press Start the lesson below and sit with your child for the teaching and the worked examples (about 19 minutes).
Let them do the practice on their own. They choose Getting started, On track or Challenge – start on On track and move up after a few right in a row.
Finish with the exit ticket and the talk question: “Why do co-interior angles add up to 180°?”
Later that day or the next day: the homework (20 minutes), then a practice test.

Watch out for

Measuring with a protractor when the diagram is not to scale. Use angle facts and write the reason.
Mixing up alternate and co-interior angles. Z shape: equal. C shape: add to 180°.

Tip for home: Find parallel lines and crossing lines in windows, railings and roads.

What your child will learn

Learning goal: use angle facts and angles in parallel lines to find missing angles, giving reasons.

Success looks like

I can use basic angle facts.
I can use angles in parallel lines.
I can give reasons for each step.

Key words

vertically opposite: equal angles opposite each other where two lines cross
alternate angles: equal angles in a Z shape
corresponding angles: equal angles in an F shape
co-interior angles: angles in a C shape that add to 180°

What to have ready

Paper and a pencil
This page on a computer, tablet or phone
For the hands-on part: Draw two parallel lines and a crossing line, measure all eight angles and spot which are equal.

The big ideas (for the adult)

Angles on a straight line add up to 180°; angles around a point add up to 360°; vertically opposite angles are equal.

Angles in a triangle add up to 180°. The two base angles of an isosceles triangle are equal.

Where a line crosses parallel lines: alternate angles are equal, corresponding angles are equal, and co-interior angles add up to 180°.

The lesson, step by step

45 minutes in 5 parts
Part	Time	How it is checked
Starter: quick recall	5 min	Graded by Classfern
Teaching input	10 min	Not assessed, self-checked
Worked examples and guided practice	9 min	Not assessed, graded by Classfern
Independent practice	15 min	Graded by Classfern
Closure and exit ticket	6 min	Graded by Classfern, self-checked

Starter, "your turn", practice and exit ticket are graded by Classfern. Worked examples and teaching are not assessed. The hands-on task and the reflection are self-assessed. Explanations in talk are judged by the parent and not recorded.

The lesson

It runs here on the page. No sign-up and no names – progress is kept only in this browser.

Homework and practice at home

20 minutes: 10 practice questions, 3 multiple-choice questions and 2 to remember from earlier work, then a short reflection. New questions every time, all graded instantly.

More practice

Grade 7 Math: Geometry Practice TestGraded instantly

All Grade 7 math lessons and tests · Math Department

Curriculum

Common Core State Standards 7.G.B.5: “Use facts about supplementary, complementary, vertical, and adjacent angles in a multi-step problem to write and solve simple equations for an unknown angle in a figure.”

Our lessons and questions are our own. They are not written or endorsed by any government department, testing agency or exam board.