Think of the 13-ft length of the ladder as the hypotenuse of a right triangle. Represent the horiz. distance from foot of ladder to base of tree by x, or 5 ft.
Represent the vert. dist. from base of tree to top of ladder by y, which is unknown.
Then (13 ft)^2 = (5 ft)^2 + y^2, or
169 ft^2 = 25 ft^2 + y^2. This simplifies to y^2 = 144. Thus y = + 12 feeet.
Note: Please pay attention to your spelling: "lader i up agenst a tree" should be "the top of a 13-ft ladder is placed against a tree."
Answer:

Step-by-step explanation:

(-1,1)(1,4)
slope = (4 - 1) / (1 - (-1) = 3/(1 + 1) = 3/2
y = mx + b
slope(m) = 3/2
use either of ur points....(1,4)...x = 1 and y = 4
now sub and find b, the y int
4 = 3/2(1) + b
4 = 3/2 + b
4 - 3/2 = b
8/2 - 3/2 = b
5/2 = b
equation is y = 3/2x + 5/2...but we need it in standard form
y = 3/2x + 5/2
-3/2x + y = 5/2.....multiply both sides by -2
3x - 2y = -5 <==== ur standard form equation
Answer:
Last answer: 
sorry couldn't find theata so I just used alpha.
29.9999 would be the answer here's how i worked it out