Let us construct the required triangle as follows:

Step 1:
Draw the base line XY of the length 3 cm.

Step 2:
Use your compass to make an arc with centre at point Y and the radius 4 cm.

Step 3:
Use your compass to make a circle with centre at point X and the radius 5 cm.

Step 4:
The point of intersection between the arcs is named as X.
The triangle is completed by joining all these three points.
Now, from above construction we see that the triangle formed is a right angle triangle.

When a line segment is perpendicular to another line segment then angle between them is ${90}^{\circ }$.

Following the above steps, we can construct a right angled triangle with the given measurements. So, the given steps are correct.

Parallel lines never intersect. Parallel lines are lines in a plane which do not meet, that is, two lines in a plane that do not intersect or touch each other at any point are said to be parallel.

We are given two angles and one side. So, data is sufficient and the triangle can be drawn.