Let AB represent the length of the ladder and AE represent the height of the platform.
Draw seg AC ⊥ seg BD.
Angle of elevation = ∠BAC = 70°
AB = 20m
AE = 2m
In right-angled ∆ABC,
sin 70° = BC/AB …..[By definition]
∴ 0.94 = BC/20
∴ BC = 0.94 × 20
= 18.80 m
In \(\Box\)ACDE,
∠E = ∠D = 90°
∠C = 90° … [seg AC ⊥ seg BD]
∴ ∠A = 90° … [Remaining angle of \(\Box\)ACDE]
∴ \(\Box\)ACDE is a rectangle. … [Each angle is 90°]
∴ CD = AE = 2 m … [Opposite sides of a rectangle]
Now, BD = BC + CD … [B – C – D]
= 18.80 + 2
= 20.80 m
∴ The maximum height from the ground upto which the ladder can reach is 20.80 metrs.