Two triangles are said to be congruent, if three sides of one triangle are equal to the three corresponding sides of another triangle. What is the name of this congruence rule?

Ithink i know it but i want to be sure so can you me out ?

Solve for n. round to the tenths place, if necessary. 14.2 cups of flour6 loaves of bread= 20 cups of flour n

Whoever gets this right gets the ! the half life of a soul smelling substance is 4 years. if you have 8 oz of this strange substance, how much of it will you have after 20 years? show work.