9514 1404 393
Answer:
the lines are perpendicular
Step-by-step explanation:
You can tell something by looking at the differences of coordinates:
B-A = (6-2, -11-5) = (4, -16) . . . . . Δy/Δx = -16/4 = -4
D-C = (-1-3, 9-10) = (-4, -1) . . . . . Δy/Δx = -1/-4 = 1/4
The product of the slopes of these lines is (-4)(1/4) = -1, so ...
the lines are perpendicular
Isn’t it supposed to be a minus sign? For it can be like w-2, w-2 ?
1. Given a group of n people. There are C(n, r) ways of forming groups of r out of n.
2. Where C(n, r)=

3. For example, given {Andy, John, Julia}. We want to pick 2 people to give a gift: we can pick {(Andy, John), (Andy, Julia), (John, Julia)}, so there are 3 ways. So we can list and count.
4. Or we could do this with the formula C(3, 2)=

5. C(8, 6)=

So there are C(8,6)=28 ways of chosing 6 out of 8 people to form the subcommittees. <span />

Point-slope form is
, where
is the slope and
is a point on the line.
Substitute in the values. 
Simplify the negative subtraction to addition. 
The formula to get the circumference is 2πr, π being pi and r being your radius.
Your r is 0.9 since the radius is half the diameter.
2πr = 2 x 3.142 x 0.9
= 5.6556cm
≈ 5.7cm