Step-by-step explanation:
the triangle URT is an Equilateral triangle so all angles are equal to 60°
and the full triangle UTS is a right angle .
5y= 90-60= 30°
y= 6
and since the triangle RST is an Isosceles triangle
so the angle RST and RTS are equal .
in this case =30° .
[tex] \sin(30) = \frac{x - 7}{11 + x - 7 } \\ \sin(30) = \frac{x - 7}{x + 4} \\ 0.5 = \frac{x - 7}{x + 4} \\ 0.5(x + 4) = (x - 7) \\ 0.5x + 2 = x - 7 \\ 0.5x = 9 \\ x = 18[/tex]
