For 26.) the two triangles are similar, so you can setup a ratio of the big triangle's perimeter to AC and set that equal to x (the small triangle's perimeter) to DF, so that:
72/22 = x/14
solve for x and you get 45.82
For 27.) I think the ratio 6/5 carries through for the entire triangle, since as far as I can tell they're similar. So I believe you can just multiply 6/5 by the smaller triangle's area to get the larger triangle's area, which results in 90 cm^2. It's been a long time since I've done geometry though, so I may be wrong.