Four friends are told that the average (mean) of their grades for their favorite class is 84.5%. Anthony got 86%, Jasmine got 92%, and Kaitlyn got 70%.

Jonathan's grade was not revealed.
What grade did Jonathan get?
PLEASE HELP SOON

Multiply the average by number of people:

84.5 x 4 = 338

This means the total of the 4 grades need to equal 338

To find Jonathan’s grade subtract the other 3 grades from 338:

338 - 86 - 92 -70 = 90

Jonathan’s grade was 90

  about 5.6 days

step-by-step explanation:

we can fill the given information into the decay equation and solve for the value of t at which half the sample remains.

the half-life is about 5.6 days.

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.