A triangle's angles will always equal up to 180. Since you already have to of the angles, you will add them up together. 30+20=50. Then, you take 180 and subtract it by the sum of the two previous angles. 180-50=130. Now you know the last angle is 130. You also know that the missing angle is also 130. The reason for that is because the two angles are the exact same if you look at it.
PEMDAS (order of operations rules) require that we perform operations in a certain order: anything inside parentheses first, followed by any exponentiation, followed by mult. and div., finally followed by addition and subtraction.
Thus, we must evaluate 5+8÷4-1 first, as it's inside parentheses. Focusing on the division first, we get 5+8÷4-1 = 5 + 2 - 1, or 6.
Then we have 5 - [6], which comes out to -1.
As with any triangle, the sum of angles is 180°.
(a)
(x -5) +(3x +30) +35 = 180 . . . . . sum of angles is 180
4x +60 = 180 . . . . . . . . . . . . . . . . collect terms
4x = 120 . . . . . . . . . . . . . . . . . . . . subtract 60
x = 30 . . . . . . . . . . . . . . . . . . . . . . divide by 4
(b)
Angle A = x -5 = 30 -5 = 25
Angle B = 3x +30 = 3*30 +30 = 120
Use the definition of tangent
or inv tangent (arctan or atan)
tan(theta) = opposite side/ adjacent side
the vertical rise would be the opposite side, the horozontal distance would be the adjacent side
let rise = y
let distance= x
x=2y
so tan(theta) = y/2y
tan(theta) = 1/2
theta = atan(1/2)
grab a handy dandy calculator, unless you know this conversion off the top of your head