What happens to a point that constantly varies in direction? a) it becomes a curve. b) it becomes a surface. c) it becomes a right line. d) it becomes a plane figure.

The question says , point varies in a direction , now when any point will vary in a direction , it will make a line .

If it varies in a direction with some angle , or we can say that the direction is also varying then it makes a curve .

If the line varies in two directions at the same time , it makes a surface ,

And

if the line varies in all directions then it makes a plane , and then it will have three coordinates.

Now here the point varies only in 1 direction . Hence it makes a line.

d. corresponding side lengths in similar triangles are proportional in length.

step-by-step explanation:

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x