The point P is the centroid of the triangle (the intersection of medians). The centroid divides the median into parts in the ratio 2:1, with the longer part between the centroid and the vertex.
If you reduce these fractions into simplest form 5/20 is 1/4 because the numerator and denominator can be divided by 5. 9/12 reduced is 3/4 because the numerator an denominator can be divided by 3.
