Step 1: Assume triangle sides using the given tangent ratio:
\[
\tan A = \frac{\text{Opposite}}{\text{Adjacent}} = \frac{3}{4}
\]
Step 2: Use Pythagoras theorem to find hypotenuse:
\[
\text{Hypotenuse} = \sqrt{3^2 + 4^2} = \sqrt{9 + 16} = \sqrt{25} = 5
\]
Step 3: Use definitions of trigonometric ratios:
\[
\sin A = \frac{3}{5}, \quad \sec A = \frac{5}{4}
\]
Final Answer:
\[
\boxed{\sin A = \frac{3}{5}, \quad \sec A = \frac{5}{4}}
\]