1. OA = a and OB = b. M is the midpoint of AB. Which expression is the vector OM?
- A½(b − a)
- Ba + ½b
- C½(a + b)
- Db − a
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Answer: C. OM = OA + ½AB = a + ½(b − a) = ½a + ½b = ½(a + b). ½(b − a) is only AM.
By Team Megalecture · Updated 4 Nov 2026
77 exam-style questions on Geometry and measures, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
77 questions · 8 topics · 10 per test
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Answer: C. OM = OA + ½AB = a + ½(b − a) = ½a + ½b = ½(a + b). ½(b − a) is only AM.
Answer: B. Area factor 80/45 = 16/9, so the length factor is 4/3 and the volume factor is 64/27. 54 × 64/27 = 128 cm3. Multiplying by the area factor gives 96 cm3.
Answer: B. 30 = ½ × 8 × 10 × sin C, so sin C = 30 ÷ 40 = 0.75 and C = 48.6°. Forgetting the ½ gives sin C = 0.375 and 22.0°.
Answer: B. 2a = (6, −4), and 2a − b = (6 − (−1), −4 − 4) = (7, −8). (5, 0) is 2a + b.
Answer: D. 2a + 6b = 2(a + 3b), so ka + 3b must be a multiple of a + 3b with the b-part 3b, giving k = 1.
Answer: B. Cosine rule: BC2 = 72 + 92 − 2 × 7 × 9 × cos 50° = 130 − 81.0 = 49.0, so BC = 7.00 cm. Forgetting the 2 gives 9.46; 49.0 forgets the square root.
Answer: B. BD = BA + AD = −p + q = q − p. p + q is the other diagonal, AC.
Answer: C. The perpendicular from the centre bisects the chord, making a right-angled triangle with sides 8 cm and d and hypotenuse 10 cm: d = √(100 − 64) = 6 cm. Adding the squares gives 12.8 cm.
Answer: B. Scale factor = 15 ÷ 6 = 2.5, so EF = 8 × 2.5 = 20 cm. Adding 9 cm to every side (17 cm) is not an enlargement.
Answer: A. Two sides and the angle between them (the included angle) are equal: SAS. We do not know the third sides, so it is not SSS.
77, each with the answer and a short explanation, across 8 topics: G1–G4, G15 Angles, polygons and bearings, G7–G8 Transformations, G9–G10 Circle theorems, G14, G16–G18 Area, volume and surface area, G5–G6, G19 Congruence and similarity, G20–G21 Pythagoras and trigonometry, G22–G23 Sine rule, cosine rule and area of a triangle, G24–G25 Vectors. Every chapter test draws ten of them, so you can take it many times.
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