Measuring Space: Perimeter and Area Mind Map

The perimeter of a polygon is the total length of all its sides.

Always check whether the question asks for boundary length or surface area before choosing a formula.

The circumference of a circle is the length of its curved boundary.

If the answer is boundary length, use 2πr or πd, not πr².

Arc length is the length of a part of a circle's circumference, and sector perimeter is the arc length plus two radii.

For sector perimeter, remember to add the two straight radii after finding the arc length.

The area of a triangle is half the product of a chosen base and its corresponding height.

Look for the right-angle mark or perpendicular height before substituting values.

Heron's formula gives the area of a triangle when the lengths of all three sides are known.

Write s = (a + b + c)/2 clearly before applying the square-root formula.

The area of a quadrilateral is the surface enclosed by a four-sided figure, found using the formula matching its shape and given conditions.

First identify the quadrilateral type and the required perpendicular height or diagonals.

The area of a circle is the surface inside its boundary, and the area of a sector is a fractional part of the circle's area.

Area uses square units and r²; circumference or arc length uses length units.

A composite figure is made by joining or removing two or more familiar shapes.

Shade or mark the required region and write plus or minus signs before calculation.