In the linear equation y = mx + b, y-intercept represents the value of y. It is the point where the line crosses the y-axis(vertical axis)
Finding the y-intercept is done by looking at which point in the graph crosses the y-axis. This point will always have an x-coordinate of zero(0).
Answer:
I believe the value would be 9.
The formula for Average speed = 
The car travels 80 km in 1 hour.
Then the car travels 90 km in 2 hours.
And finally the car travels 76 km in 1 hour
So the total distance covered by the car = 80 + 90 + 76 = 246 km
The total time taken to cover this distance = 1 + 2 + 1 = 4 hours.
So average speed = 
The average speed of the car is 61.5 km / h
Chris is going 10 mph. After 9 hours, Chris has gone 90 miles. Elena is going 14 mph. After 9 hours, she has gone 126 miles. 126 miles is 36 miles more then 90 miles.
There is no figure.
but you can use A^2 + B^2 = C^2
C is your hypotenuse.
so if you have the other two lengths if you square them and add them you'll have C squared. So you'll have to find the square root of that number to actually find the length.