Length of an Arc and Sector Perimeter
Arc length is the length of a part of a circle's circumference, and sector perimeter is the arc length plus two radii.
Practice This ConceptMain explanation
Teacher explanation
A sector is like a slice of a circle. Its curved part is only a fraction of the full circumference, decided by the central angle.
Example
For radius 14 cm and angle 90°, arc length = 90/360 × 2 × 22/7 × 14 = 22 cm; sector perimeter = 22 + 14 + 14 = 50 cm.
Simple analogy
Sector boundary has one curve and two radii.
Common confusion
Students often give only arc length when the question asks for the perimeter of a sector.
Exam tip
For sector perimeter, remember to add the two straight radii after finding the arc length.
Answer writing and exam use
1-mark use
Write the exact meaning of length of an arc and sector perimeter in one clean line.
2-mark use
Define length of an arc and sector perimeter and add one example or condition.
3-mark use
Explain length of an arc and sector perimeter, show the method or example, and mention the common mistake.
Practice this concept with focused MCQs
Open the concept quiz intro first, review the test details, and then start a focused MCQ set from this concept only. Instant score and answer review are live now.
Help improve this page
Found something confusing, incorrect, or missing?