Use pythagorean theorem for all of them
a. 3, 4, 5
3^2+4^2?5^2
9+16?25
25=25
right
b. 5, 6, 7
5^2+6^2=7^2
25+36=49
61>49
acute
c. 64+81=144
145>144
acute
hope this helps!
In this example, y is equal to 8.
In order to find this, first note that the two x value expressions create a straight line. That means when we add them together they will equal 180. this will give us a value for x.
x + 10 + 10x - 61 = 180
11x - 51 = 180
11x = 231
x = 21
Now that we have the value of x, we can do the same for the straight line created by the x + 10 angle and the 18y + 5 angle.
x + 10 + 18y + 5 = 180
(21) + 10 + 18y + 5 = 180
36 + 18y = 180
18y = 144
y = 8
That's vertex form for a parabola 
and we read off vertex (p,q) as
Answer: Vertex (5,7)
The negative <em>a</em> tells us this is a downward opening parabola (upside down from the usual 
. I remember CUP - Concave Up Positive; here <em>a </em>is negative so not a cup, instead concave <em>down.</em> The same rule applies to second derivatives in calculus so memorize it now and use it later.
Answer: downward
Well I don't know if you are looking for the variable but here it is :)
