The first tree is 80 ft tall and is 1200 ft from the vanishing point and the third tree is drawn 600 ft from the vanishing point.

What would be the height of the third tree?

Please make bigger so I can see

Step-by-step explanation:

a) At 10 minutes the line is at y - 1, which means she reached 1 km in 10 minutes.

b) The last 30 minutes would be 30 minutes to 60 minutes.

at 30 minutes she was at 0km at 60 minutes she was at 4 km, so in 30 minutes she traveled 4 km.  30 minutes is a half hour, so multiply distance by 2: 4 x 2 = 8, she was traveling at 8 km per hour.