You add all the sides together, a good way to remember it is "perimeter, plus"
Notice the picture below
the AD line is a bisector, cutting the 36 degrees A in half,
18 and 18 degrees each half
notice the tickmarks, the triangle is an isosceles,
if those two sides are equal, so are the angles they make
down below with the base
now, the base is 8, AD is bisecting that too, to 4 and 4
now, using the Law of Sines

keep in mind, the angles are in degrees, so, when taking the sines, make sure your calculator is in Degree mode
Answer:
Its either answer B. or D. Sorry if I'm wrong and I hope this sorta helps.
Answer:
B) The sum of the squared residuals
Step-by-step explanation:
Least Square Regression Line is drawn through a bivariate data(Data in two variables) plotted on a graph to explain the relation between the explanatory variable(x) and the response variable(y).
Not all the points will lie on the Least Square Regression Line in all cases. Some points will be above line and some points will be below the line. The vertical distance between the points and the line is known as residual. Since, some points are above the line and some are below, the sum of residuals is always zero for a Least Square Regression Line.
Since, we want to minimize the overall error(residual) so that our line is as close to the points as possible, considering the sum of residuals wont be helpful as it will always be zero. So we square the residuals first and them sum them. This always gives a positive value. The Least Square Regression Line minimizes this sum of residuals and the result is a line of Best Fit for the bivariate data.
Therefore, option B gives the correct answer.