Answer:
1) d
2) d
3) yes
4) no
5) B
Explanation:
1) Angle opposite the longest side is the greatest.
AB < BC < AC
Therefore,
Angle C < Angle A < Angle B
2) angle A = 180 - 55 - 45 = 80
Angle B < Angle C < Angle A
AC < AB < BC
3) 9, 12, 15
To form a triangle;
longest side < sum of two shorter
sides
15 < 9 + 12
15 < 21 is a true statement
4) 4, sqrt(12), 7
To form a triangle;
longest side < sum of two shorter
sides
7 < 4 + sqrt(12)
7 < 7.46 is a false statement
5) To form a triangle;
longest side < sum of two shorter
sides
This is satisfied only in B
19 < 9 + 11
19 < 20 is a true statement