Im trying to do IXL and I dont understand the way my teacher teaches (ironic right?) the points (-2,-10) and (8,r) fall on a line with a slope of 1/10. What is the value of r?

Acircle has a radius of 5/6 units and is centered at (3.6, 7.8) write the equation of this circle

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

Sum is 17 and their difference is 3