This is an isosceles triangle. Therefore, at the base we have congruent angles (look at the picture).
We have the equation:
(5x + 13)° + (3x + 7)° = 180°
5x + 13 + 3x + 7 = 180 <em>combine like terms</em>
(5x + 3x) + (13 + 7) = 180
8x + 20 = 180 <em>subtract 20 from both sides</em>
8x = 160 <em>divide both sides by 8</em>
<h3>x = 20</h3>
Answer: option C
Step-by-step explanation:
The diagram of the triangle is shown in the attached photo. The triangle is a right angle triangle ABC
Assuming the given angle is #,
Recalling the trigonometric ratio,
tan # = opposite / adjacent
If tan # = 4, it means
opposite / adjacent = 4/1
Therefore, opposite = 4 and adjacent = 1
Applying Pythagoras theorem,
Hypotenuse^2 = opposite ^2 + adjacent ^2
Hypotenuse = AC
Opposite = 4
Adjacent = 1
AC^2 = 4^2 + 1^2 = 17
AC = ± √17
To determine cos #, we would apply another trigonometric ratio,
Cos# = adjacent /hypotenuse
Cos# = 1/±√17
Cos # =-1 /√17 or 1/√17
