In ` Delta ABC ` , if a = 3, b = 4 and sin B = 1 , find sin A

Answer

To solve for sin A in triangle ABC given that a = 3, b = 4, and sin B = 1, we can use the sine rule. The sine rule states that:

\[ \frac{a}{\sin A} = \frac{b}{\sin B} \]

### Step 1: Substitute the known values into the sine rule.

We know:
- a = 3
- b = 4
- sin B = 1

Substituting these values into the sine rule gives us:

\[ \frac{3}{\sin A} = \frac{4}{1} \]

### Step 2: Simplify the equation.

This simplifies to:

\[ \frac{3}{\sin A} = 4 \]

### Step 3: Cross-multiply to solve for sin A.

Cross-multiplying gives:

\[ 3 = 4 \cdot \sin A \]

### Step 4: Isolate sin A.

To isolate sin A, divide both sides by 4:

\[ \sin A = \frac{3}{4} \]

### Conclusion:

Thus, the value of sin A is:

\[ \sin A = \frac{3}{4} \]