Introduction to Trigonometry — Maths STD 10 — Question
Gujarat BoardEnglish MediumSTD 10MathsIntroduction to Trigonometry1 Mark
Question
If $\angle A$ and $\angle B$ are acute angles such that $cos\ A = cos\ B$ then show that $\angle A = \angle B$.
✓
Answer
In right triangle $ABC,$
$\cos A = \frac { A C } { A B } \ and \cos B = \frac { B C } { A B }$
But cos A = cos B [Given]
$\Rightarrow \frac { A C } { A B } = \frac { B C } { A B } \Rightarrow _ { A C } = B C$
$\Rightarrow \angle A = \angle B$
[Angles opposite to equal sides are equal]
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.