Answer:
3, 6, 7, 9
Step-by-step explanation:
1/3 = 0.33...
1/6 = 0.1666...
1/7 = 0.1428571428...
and 1/9 = 0.11...
The mean of the data is given

The variance of the data is given

Only triangles , there isosceles if they both have two congruent sides & angles !