Question

a person moves 50 meter North then 40 m East then 20 m South find the displacement

Answer 1

We nee AD,

At C, he turned South West, so it would be 45 Degrees to the current path of Travel, And It would normally intersect AB at 45 Degrees.

Now in Triangle BCE

We know Angle C is 45, and Angle E is 45 as Angle B is 90 (180–90–45)

As Angles E and C are 45, that implies, sides CB and BE are also identical in length. 20 kms. And say Side CE = a

==> a^2 = 20^2 + 20^2

==> a = 20√2

As we know, CD = 30√2

==>ED = CD-CE = 30√2 - 20√2 = 10√2

Now in Triangle ADE, ED = 10√2 and AE = (30–20) = 10

And we know Angle A = 90

S0,

DE^2 = AE^2 + AD^2

==> (10√2)^2 = 10^2 + AD^2

==> AD = Sqrt(200–100) = 10 m