Can you me answer this problem
naomi has earned $54 mowing lawns the past two days. she worked 2 1/2 hours yesterday and
4 1/4 hours today. if naomi is paid the same amount every hour she works, how much does she earn per hour to mow lawns?

You need to find "dollars per hour". So you need to know the total dollars and the total hours.

You already know the total dollars ... it's 54.

What are the total hours ?    2-1/2  plus  4-1/4  .  Can you add those ?

Once you add up the total hours, divide ($54) divided by (total hours).

The quotient is the number of dollars she earns for each hour she works.

No a triangle cannot be formed because when you add the two smallest number together (which would be 11) the have to be bigger than the number it is "against" ( which would be 12)