BC=60 cm because FG is the midsegment of triangle ABC so it separates the sides of the triangle into two equal segments and 30(2)=60.
GF=22 cm because according to the Triangle Midsegment Theorem, GF=1/2(AC). GF=1/2(44 cm). GF=22 cm. Next, we can conclude EG and DA are 22 cm because the diagram marks them as congruent. So CD=44 cm+22 cm=66 cm. Then, we find that EF=EG+GF=22 cm+22 cm=44 cm. So, using the Trapezoid Midsegment Theorem, we know that KM=1/2(DC+EF). KM=1/2(66 cm+44 cm). KM=1/2(110 cm). KM=55 cm.
Hope this helps and makes sense!