Answer:
y = 25.20 m
Step-by-step explanation:
By applying tangent rule in ΔABC,
tan(25)° = [tex]\frac{\text{Opposite side}}{\text{Adjacent side}}[/tex]
= [tex]\frac{y}{BC}[/tex]
BC = [tex]\frac{y}{\text{tan}(25)}[/tex] --------(1)
Now we apply tangent rule in ΔABD,
tan(15)° = [tex]\frac{y}{BC+CD}[/tex]
tan(15)° = [tex]\frac{y}{BC+40}[/tex]
BC + 40 = [tex]\frac{y}{\text{tan}(15)}[/tex]
BC = [tex]\frac{y}{\text{tan}(15)}[/tex] - 40 -------(2)
From equation (1) and (2),
[tex]\frac{y}{\text{tan}(25)}=\frac{y}{\text{tan}(25)}-40[/tex]
[tex]\frac{y}{\text{tan}(25)}-\frac{y}{\text{tan}(25)}=-40[/tex]
[tex]y[\frac{1}{\text{tan}(25)}-\frac{1}{\text{tan}(25)}]=-40[/tex]
y(2.1445 - 3.7321) = -40
1.5876y = 40
y = 25.1953
y ≈ 25.20 m
Therefore, measure of y is 25.20 m.
