Step-by-step explanation:
In traingle ABC
[tex]\\ \sf\longmapsto 40+90+<B=180[/tex]
[tex]\\ \sf\longmapsto <B+130=180[/tex]
[tex]\\ \sf\longmapsto <B=50°[/tex]
Now
[tex]\\ \sf\longmapsto x+100+50=180[/tex]
[tex]\\ \sf\longmapsto x=30°[/tex]
Answer:
In ΔABC ,
∠A + ∠ACB + ∠B = 180 {Angle sum property of triangle}
40 + 90 + ∠B = 180
130 + ∠B = 180
∠B = 180 - 130
∠B = 50
In ΔBFD ,
∠D + ∠B + ∠BFD = 180
x + 50 + 100 = 180
x + 150 = 180
x = 180 - 150
x = 30°
