Label 3 vertices of the triangle and the foot of the altitude of it A,B,C and D respectively, where AB=4.3cm, AC=3.1cm and AD=2.5cm. Infinite number of triangles can be drawn changing, for instance, the direction of the altitude. So, place the base BC to be level and the vertex A above. First, draw a level line segment PQ on which BC is placed and the altitude AD stands upwards. So, the length of PQ must be at least two times longer than that of AB=4.3cm. Fix the stylus of compass to P and set the compass width a little across the middle of PQ. Draw an arc crossing an imaginary vertical bisector of PQ above and below the line. Keeping the compass width, repeat the same process from Q. So that the last arc cuts across the first one at 2 points. Draw a vertical line thru the 2 crossing points above and below PQ. The line is perpendicular to PQ. Label the crossing of the 2 lines D. Set the compass width to AD=2.5cm, and draw an arc from D crossing the bisector above PQ. Label the crossing A. Set the compass width to AB=4.3cm, and draw an arc from A crossing PQ on the left side of D. Label the crossing B. Again, set the compass width to AC=3.1cm, and draw an arc from A crossing PQ on the right side of D. Label the crossing C. Draw 2 lines connecting A,B and A,C. This is the triangle ABC drawn using 2 given sides AB and AC, and a given altitude AD. ( the length of BC is almost equal to 5.3cm )