Question

A ladder on the platform of a fire brigade van can be elevated at an angle of 70° to the maximum. the length of the ladder can be externded upto 20m. if the platform is 2m above the ground,find the maximum height from the ground upto which the ladder can reach. (sin70° =0.94)

Answer 1

Length of Ladder, the height it can reach forms a right angled triangle

where perpendicular P = Height it can reach

and hypotenuse H = Length of Ladder

So, applying trigonometric formula, we have

sin Ф = P / H

Ф = 70° at maximum

sin 70° = P / 20

0.94 = P / 20

P = 20 * 0.94

P = 18.8 m

Now, Ladder is placed 2m above ground, so

Height from ground it can reach = 18.8 + 2 = 20.8 m

therefore, it can reach maximum 20.8 m from the ground.

Answer 2

In the attachment I have solved this problem with diagram.

Calculations are clear and easy to
understand.

In the diagram
AB is the ladder
BD Maximum possible height of the
ladder from the ground.

I hope this answer help you