Today’s problem — free all day, every step. Every day has one.
Angles on a line — two equal ones and 62°
Two equal angles sit on a straight line together with a third angle of 62 degrees. Find the size of each equal angle.
The pattern behind it: Angle chasing
One angle gives you the next, until you reach the angle asked for.
In this one. Angles on a straight line add up to 180°, so take away the angle you know and let the two equal angles share what is left — half each.
How to spot it
A figure has several angles marked with only one or two values given, and words like 'isosceles', 'parallel', or 'straight line' point to which rule to use first.
Common mistake
Children apply an angle rule to the wrong triangle or the wrong straight line in a crowded figure, or stop one step before the angle actually asked for.
Try one like it
Standard Triangle PQR — angle Q is twice angle R In triangle PQR, angle P = 48 degrees and angle Q is twice angle R. Find the size of angle R.The 33 problem patterns
All 33 patterns, one to a page — the 19 behind Primary 5 and 6 word problems, and the skills the younger years are built on. The bar model, how to spot it in the question, and the mistake children make. A booklet you can print. Free.
A PDF, and a note when new solutions go up.