Given at the question number 1:
A triangle with the measure of angles are :
x , 3x and (x + 5 )
We should know that : the sum of the angles of the triangle = 180
So,
[tex]x+3x+(x+5)=180[/tex]
Solve the equation to find the value of x:
[tex]\begin{gathered} x+3x+(x+5)=180 \\ x+3x+x+5=180 \\ 5x=180-5 \\ 5x=175 \\ \\ x=\frac{175}{5}=35 \end{gathered}[/tex]
The measure of the angle B = 3x = 3 * 35 = 105
So, the answer is option D. 105
