The Pizza Cutter Lab
Arc Length & Sector Area (Edexcel 4MA1 Section 4.9)
"Forget the formulas. It's just a pizza slice. How much of the pizza did you eat?"
The Pizza Lab
The Logic Track
🧠 The Common Sense Check
Quarter pizza! One-fourth of the circle. So the area is just ¼ of πr² = 78.54 cm².
🍕 Arc Length (The Crust)
The curved edge only. It's 1/4 of the full circumference (πD).
🧀 Sector Area (The Cheese)
The flat surface inside. It's 1/4 of the full area (πr²).
⚠️ The Perimeter Trap
"Imagine walking around the slice. You walk the curve, but you also have to walk back to the center and out again. That's +2r!"
🎯 Real Exam Scenario
In real exams, they'll give you the angle and radius. You need to find BOTH the arc length AND the area. Don't mix them up!
The Sector Solver
(Following Edexcel Mark Scheme Standards)Given Information:
Examiner's Mark Scheme Tip:
With "nice" angles like 90°, you can use fractions instead of decimals. The mark scheme accepts both, but fractions are often cleaner!
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