To calculate the area of a circle, we use the formula:

$A = \pi r^2$

where:

• $A$ is the area,
• $r$ is the radius of the circle,
• $\pi \approx 3.14159$.

Given that the radius $r = 1$, we substitute that into the formula:

$A = \pi \times (1)^2 = \pi \approx 3.14159$

So, the area of the circle is approximately:

$A \approx 3.14159 \text{ square units}.$

Would you like more details on how this formula is derived or have any further questions on circles?

Here are 5 related questions you might find interesting:

1. How does the area of a circle change if the radius doubles?
2. What is the formula for the circumference of a circle?
3. How do you calculate the area of a sector of a circle?
4. How is the area of a circle related to its circumference?
5. How do you calculate the volume of a sphere with radius 1?

Tip: To get a quick estimate of $\pi$, you can use $22/7$, which is a common approximation.