10 questions · Form 3 Mathematics Bab 8: Loci in Two Dimensions
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Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. A point P moves such that it is equidistant from vertices B and C of an equilateral triangle ABC. Which line segment represents the locus of P?
Answer: B
The locus equidistant from two points B and C is the perpendicular bisector of segment BC, which passes through vertex A in an equilateral triangle.
2. What is the definition of a locus in 2D space?
Answer: B
A locus is a set of points or a path traced out by a moving point that satisfies one or more given rules.
3. If Locus 1 is a circle of radius 4 cm centred at (0,0) and Locus 2 is a circle of radius 2 cm centred at (0,0), how many points of intersection exist between Locus 1 and Locus 2?
Answer: A
Concentric circles of different radii never touch or cross, so there are 0 points of intersection.
4. A goat is tied to a stake in an open field with a 4-metre rope. What is the locus of the maximum area the goat can reach?
Answer: B
Tied to a fixed stake (fixed point) with a 4 m rope, the boundary of the movement is a circle of radius 4 m.
5. What is the locus of a point moving at a fixed distance d from a straight line AB?
Answer: C
Points at a constant distance from a straight line form two parallel lines running on both sides of the line.
6. Point M is 5 cm away from line L. How many points on line L are at a distance of 8 cm from point M?
Answer: C
Since the distance from M to line L (5 cm) is less than 8 cm, a circle of radius 8 cm centred at M intersects line L at 2 points.
7. Two parallel lines are 6 cm apart. What is the distance from either parallel line to the locus of points equidistant from both lines?
Answer: B
The locus lies midway between the two parallel lines, so its distance from either line is 62 = 3 cm.
8. In a rectangle PQRS, what is the locus of a point moving equidistant from line PQ and line SR?
Answer: B
PQ and SR are parallel lines. The locus equidistant from two parallel lines is a parallel line halfway between them.
9. If a point moves inside a square ABCD such that it is always equidistant from side AB and side AD, what is its locus?
Answer: A
Sides AB and AD intersect at vertex A. The locus equidistant from two intersecting sides is the angle bisector of angle DAB, which is diagonal AC.
10. What geometric path is formed by a point moving equidistant from two intersecting lines?
Answer: B
Points equidistant from two intersecting lines lie on the angle bisector of the angle formed between those lines.