How does velocity-time graph give a geometrical way of calculating the distance covered from time t to time t'?

Slope of a velocity-time graph gives

Study the velocity-time graph and calculate: The distance covered in region BCFE

Study the velocity-time graph and calculate: The distance covered in region ABE.

The velocity time graph shows the motion of a cyclist Find the distance covered by the cyclist in 15 seconds.

The velocity time graph shows the motion of a cyclist Find its velocity.

The velocity time graph shows the motion of a cyclist Find its acceleration.

Study the velocity-time graph and calculate: The acceleration from A to B

Draw velocity-time graph for a body moving with uniform velocity. Hence show that the area under the velocity-time graph gives the distance travelled by the body in a given time interval.

The velocity time graph represents motion of an object for 350s. Calculate the acceleration of the object for the time internal 100 sec