Parallel Lines — Class 9 Maharashtra SSC Mathematics revision notes
A 4-page visual revision sheet for Parallel Lines, written for Class 9 Maharashtra SSC Mathematics. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
Page 1 as PDF
Parallel Lines in one look
one transversal, eight angles, and the three pairs that carry every result
The setup, and the names of the angle pairs
- two lines in a plane are parallel when they never meet however far they are produced
- a transversal is a line cutting two or more lines at distinct points, and it creates eight angles in all
- corresponding angles sit in matching positions at the two crossings, one above and one below, both on the same side
- alternate angles sit on opposite sides of the transversal, the interior pair lying between the two lines
- co-interior angles, also called allied, lie between the two lines and on the same side of the transversal
- these names apply whether or not the lines are parallel. It is only the equalities below that need parallelism
The three properties, when the lines are parallel
- Corresponding: equal. The pair in matching positions at the two crossings have the same measure. This is usually taken as the axiom the other two are proved from
- Alternate: equal. The pair on opposite sides of the transversal, whether both interior or both exterior, have the same measure
- Co-interior: supplementary, adding to 180°. This is the one pair that is NOT equal, and treating it as equal is the classic error
- The converses: each runs backwards too: if a pair of corresponding angles is equal, or alternate angles are equal, or co-interior angles add to 180°, then the lines are parallel
Page 1 of 4. The full sheet, all 4 pages, opens free in the app.
What this Parallel Lines sheet covers
- Transversal
- Corresponding angles
- Alternate angles
- Interior angles
- The setup, and the names of the angle pairs
- Properties of parallel lines
- The three properties, when the lines are parallel
- Corresponding
- Alternate
- Co-interior
- The converses
- Angles that need no parallelism at all
- Finding every angle from one
- Solving for an unknown
- Converse properties
- Test for parallel lines
- Proving two lines are parallel
- Which relation belongs to which pair
- Where this chapter is used later
- Terms in this chapter
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Mathematics chapter by chapter against your real exam dates and free hours, and when the plan reaches Parallel Lines the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.