Determines whether the line through the points
s (-2.3) and r (3,5) is perpendicular to the line through the points a (2, -1) and b (-4, 14)
: 3

Pls! does anybody know a shortcut for answering these types of questions in the future?

The center of a circle represent by the equation (x+9)^2+(y-6)^2=10^2 (-9,6), (-6,9), (6,-9) ,(9,-6)

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