Line NM is 9 and the measure of angle MLN is 58 degrees. This is because both triangles are equal in length, size, and angle measures. The triangle to the right is just rotated and reflected.
First you need to find out how many moles of AsF3 are in 1.92 grams.
The molar mass of AsF3 is 131.918 g/mole so
1.92 g * (1 mole)/(131.918g) = .0146 moles AsF3
Each mole of AsF3 has 6.02 x10^23 molecules of AsF3 and each molecule of AsF3 has 3 flourines, so you need to convert from moles to molecules AsF3 to atoms of F
0.146 moles AsF3 * (6.02 x 10^23 molecules AsF3)/(1 mole AsF3) * (3 atoms F)/(1 molecule AsF3) = 2.64 x 10^22 atoms F
Primes are
2,3,5,7,11,13...
ok, so it must be multiplule of 2,7 and 11
2*7*11=154
answer is 154