Q1. [1] straightforward initial-understanding
Which of the following correctly defines tan A in a right triangle ABC, right-angled at B?
(A) AB/AC
(B) BC/AC
(C) BC/AB
(D) AC/BC
- A AB/AC
- B BC/AC
- C BC/AB
- D AC/BC
Generated by claude-sonnet-4-6 · 2026-06-15 10:21 · grounding rag
Model Answer
(C) BC/AB
In a right triangle ABC, right-angled at B, $\tan A = \dfrac{\text{side opposite to angle A}}{\text{side adjacent to angle A}} = \dfrac{BC}{AB}$.
Source: Chapter 8, Section 8.2 Trigonometric Ratios
Explanation
- BC is opposite to ∠A, and AB is adjacent to ∠A; AC is the hypotenuse.
- Students commonly confuse tan with sin (BC/AC) — remember tan uses no hypotenuse.
- The mnemonic TOA (Tan = Opposite/Adjacent) helps recall this quickly.