Answer:
A,C,D are triangles, B is not.
Step-by-step explanation:
Let 3 sides of a triangle be a,b,c.
A triangle have the sum of 3 angles = 180 degree
and
a-b<c<a+b (similar for a and b)
a. three sides measuring 6 cm, 8 cm, and 10 cm
Satisfied the a-b<c<a+b property -> triangle
b. three angles measuring 40 degrees, 70 degrees, and 65 degrees
Total of 3 angles = 40+70+65 = 175 > 180
-> not triangle
c. three angles measuring 10 degrees, 25 degrees, and 145 degrees
Total of 3 angles = 10+25+145 = 180
-> triangle
d. three sides measuring 9 m, 15 m, and 9 m
Satisfied the a-b<c<a+b property -> triangle
