Area of Circle and Triangle

• Area is the measure of the two-dimensional space inside a closed shape
• Area is always expressed in square units (e.g., square meters (m²), square feet (ft²), square inches (in²), etc.)

Circle

• A circle is a set of all points in a plane that are at a fixed distance from a center point
• Radius (r): The fixed distance from the center of the circle to any point on the circle
• Diameter (d): The distance across the circle through the center, and is twice the radius (d = 2r)
• Pi (π): A mathematical constant approximately equal to 3.14159, representing the ratio of a circle's circumference to its diameter
• Area of a Circle: A = πr², where r is the radius of the circle

Triangle

• A triangle is a polygon with three edges and three vertices
• Base (b): One side of the triangle, usually the bottom side
• Height (h): The perpendicular distance from the base to the opposite vertex
• Area of a Triangle: A = 1/2 * b * h, where b is the base and h is the height

Parallelogram

• A parallelogram is a quadrilateral with two pairs of parallel sides
• Base (b): One of the sides of the parallelogram
• Height (h): The perpendicular distance between the base and its opposite side
• Area of a Parallelogram: A = b * h, where b is the base and h is the height

Square

• A square is a quadrilateral with four equal sides and four right angles
• Side (s): The length of one side of the square
• Area of a Square: A = s², where s is the length of a side

Rectangle

• A rectangle is a quadrilateral with two pairs of equal sides and four right angles
• Length (l): The longer side of the rectangle
• Width (w): The shorter side of the rectangle
• Area of a Rectangle: A = l * w, where l is the length and w is the width