What step must be taken first if a 3D geometry question provides a diameter but the formula requires rrr?
Halve the diameter to find the radius (r=d2r = \frac{d}{2}r=2d).
Flashcards for Edexcel IGCSE Maths Spheres and Cones, covering the key terms, formulae and methods you need to recall for Paper 1 and Paper 2. 20 cards, matched to the Edexcel IGCSE Maths (4MA1) specification.