How to draw an Isosceles triangle given the perimeter and altitude

Draw line AO which is half the perimeter of the triangle
At point O construct a perpendicular and measure off the altitude upto point C
Join A to C and bisect it and enlongate it until it intersects line AO at point P
Join point P to point C
Measure off distance OP and using O as the centre maintain the same distance and mark off distance OM
Join point M to point C
APM is the required Isosceles triangle