OABC is a parallelogram. (OA) ⃗ = a and (OC) ⃗ = c

Question

M is the mid-point of OB.

Find (MA) ⃗ in terms of a and c.

Answer 1

Since M is the mid-point of OB, we have:

(MA) ⃗ = (MO) ⃗ + (OA) ⃗

Since OABC is a parallelogram, we have:

(MO) ⃗ = (OC) ⃗ = c

Therefore,

(MA) ⃗ = c + a

So, in terms of a and c, (MA) ⃗ is equal to c + a.