Answer:
a. yes, see answer for reasoning
b. no, see answer for reasoning
Explanation:
to determine the possibility of a triangle, you must know that for any a,b,c side lengths of a triangle, these must be true:
a+b>c
a+c>b
b+c>a
this means that the sums of the measures of two legs of a triangle must be greater than the measure of the remaining leg.
a. 7+8.7=15.7> 15.4 yes
7+15.4=22.4>8.7 yes
8.7+15.4=24.1>7 yes
this triangle is possible.
b. 12+5=17 is NOT > 18.9
the above reasoning is not true, so this triangle is impossible.