Annotating the exam diagram in the first minute
Mark right angles, equal lengths and parallel ticks before choosing a formula.
Key formulas
Silent reading
Transfer every worded fact onto the figure. If the text says AH ⊥ plane, draw the square corner yourself.
What to avoid
Do not invent equal lengths because they look equal. Only mark what is stated or already proved.
Payoff
Annotated diagrams cut algebra mistakes; you see which triangle owns which length.
Worked example
Worked example
Problem. A diagram shows pyramid S-ABCD with “SA perpendicular to the base”. What should you mark in the first 30 seconds?
Solution. Mark a right-angle square where SA meets the base at A (or the foot if differently named), tick any equal edges stated in the text, and label the target length/angle. Do not mark equal lengths that only look equal.
Tick system
One tick for first equal pair, two ticks for another pair — keep them distinct.
Review quiz
Which should you NOT mark from appearance alone?
Practice questions
- List five symbols you should add to a blank geometry diagram.
- Explain why “looking equal” is not a reason.
Study notes
Should I redraw?
If the printed diagram is tiny or crowded, a larger redraw can be worth 20 seconds.