Question

In $\Delta ABC$, right-angled at $B$, $AB=24$ cm, $BC=7$ cm. Determine:
(i) $\sin A,\cos A$
(ii) $\sin C,\cos C$

Answer 1

$\angle B={90}^o$

$A{C}^2=A{B}^2+B{C}^2$ ...(Pythagoras theorem)

$A{C}^2=(24{)}^2+(7{)}^2$

$AC=25$

(i) $\sin A=\frac{BC}{AC}=\frac{7}{25}$, $\cos A=\frac{AB}{AC}=\frac{24}{25}$

(ii) $\sin C=\frac{AB}{AC}=\frac{24}{25},\cos C=\frac{BC}{AC}=\frac{7}{25}$