# Whats the formula to find the area of a circle?

## Could you please check my work and help me with a couple.

An airplane that flies at 100 km/h with a 10 km/h tailwind travels at 110 km/h relative to the ground. If it instead flies into a 10 km/h headwind, its groundspeed is :

110 km/h /2= 55 km/h

The average speed of a horse that gallops a distance of 10 kilometers in a time of 30 minutes is

(10 km)(30 min)= 300 km

What is the acceleration of a car that maintains a constant velocity of 100 km/hr for 10 seconds?

100 km/hr /10 s= 10 km/h s

Ten seconds after starting from rest, an object falling freely downward will have a speed of about (This question I don't understand)

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? (This one I don't understand)

If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about

would it be 10 m/s?

A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. How far below the level from which it was thrown is the rock 2 seconds later?

(4.9 m/s)(2 s)=9.8 m

## To find the area of a circle, you can use the formula:

A = π * r^2

where A represents the area of the circle, π (pi) is a mathematical constant approximately equal to 3.14159, and r is the radius of the circle.

To calculate the area, square the value of the radius and then multiply it by pi. The radius is the distance from the center of the circle to any point on its edge.

## areacircle=PI*radius^2

## Could you please check my work and help me with a couple.

An airplane that flies at 100 km/h with a 10 km/h tailwind travels at 110 km/h relative to the ground. If it instead flies into a 10 km/h headwind, its groundspeed is :

110 km/h /2= 55 km/h

The average speed of a horse that gallops a distance of 10 kilometers in a time of 30 minutes is

(10 km)(30 min)= 300 km

What is the acceleration of a car that maintains a constant velocity of 100 km/hr for 10 seconds?

100 km/hr /10 s= 10 km/h s

Ten seconds after starting from rest, an object falling freely downward will have a speed of about (This question I don't understand)

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? (This one I don't understand)

If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about

would it be 10 m/s?

A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. How far below the level from which it was thrown is the rock 2 seconds later?

(4.9 m/s)(2 s)=9.8 m