It takes jessica 1 hour 45 minutes to mow and trim the lawn. it takes felecia and jessica 1 hour to do the lawn. how long will it take felecia on her own?

This kind of problem request the use of harmonic mean:

if t₁ is the Time spent by Jessica, and
t₂, the time spent by Felecia, and t₃ the time spent by both, then the equation of that kind of problem will be:

1/t₁ + 1/t₂ =1/t₃.

t₁ = 1h45 min, t₂ (unknown, to be calculated), t₃ = 1 h, to ease things let' convert the time in minutes

t₁ = 105 min

t₂ = ?(time needed to Felicia to  maw the lawn)

t₃ = 60 min

1/105 +1/t₂ = 1/60===> 1/t₂ = 1/60 - 1/105==> 1/t₂ =1/140

& t₂ =140 minutes or t₂ = 2h & 20 min

28.07 degrees

Step-by-step explanation:

To figure out these questions, you need to know inverse sin. To solve this question you do inverse sin (8/17) to get 28.07 degrees. You need to apply sin because it is opposite (8) over hypotenuse (17). Then, you need to make it inverse because you are figuring out the angle measure.