Anationwide survey of 100 boys and 50 girls in the first grade found that the daily average number of boys who are absent from school is 15, with a standard deviation of 7. for girls, the average number of absentees is 10, with a standard deviation of 6. the standard deviation of the difference is

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.