Answer:
1. no, 2. yes
Explanation:
You need to use the triangular inequality thereom, which goes by if any side lengths are added together, they are greater than the remaining one. So, for number one, although 20+9=29>8 and 20+8=28>9, 9+8<20 since 9+8=17, which is less than 20. For number two, yes because 1) it is a right triangle triple and 2) 3+4=7>5, 4+5=9>3, and 5+3=8>4.