Evaluate 10m+n²/4 when m=5 and n=4

the first domain and range set to the left is matched with the top relation, and the second set the set in the middle goes with the bottom relation.

can someone me: the midsegment through the legs of an isosceles triangle is 4 in. find the sides of the triangle if its perimeter is 20 in. ,   and point g is the centroid of the right △abc with hypotenuse ab=18 in. find cg.