Maths Olympiad Prep

Library / /67 of 520

Geometry Difficulty 6.4 National olympiad Find the answer

Can the distances from a certain point on the plane to the vertices of a certain square be equal to 1,4,71, 4, 7, and 88 ?

Solution

1. Identify the problem: We need to determine if there exists a point on the plane such that the distances from this point to the vertices of a square are exactly 1, 4, 7, and 8 units.

2. Use the distance formula: Let the vertices of the square be A,B,C, A, B, C, and D D . Let the point be P P . The distances from P P to A,B,C, A, B, C, and D D are given as 1, 4, 7, and 8 units.

3. Apply the distance relationship: For a point P P to have these distances to the vertices of a square, the sum of the squares of the distances from P P to opposite vertices must be equal. This is derived from the properties of a rectangle (and hence a square).

4. Check the sum of squares:
12+82=1+64=65 1^2 + 8^2 = 1 + 64 = 65
42+72=16+49=65 4^2 + 7^2 = 16 + 49 = 65
Both sums are equal, which is a necessary condition for the distances to be from a point to the vertices of a rectangle.

5. Analyze the side length of the square: For a square, the side length s s must satisfy the Pythagorean theorem in the context of the distances from P P to the vertices. The side length s s must be such that the distances from P P to the vertices form a valid geometric configuration.

6. Determine the range of side lengths: The side length s s of the square must be in the range where the distances from P P to the vertices can form a square. This involves checking the possible configurations:
- For a square with side length s s , the distances from P P to the vertices must fit within the constraints of the square's geometry.
- The side length s s must be such that the distances 1, 4, 7, and 8 can be realized.

7. Check the feasibility: Given the distances 1, 4, 7, and 8, we need to check if there exists a side length s s that fits within the constraints:
- The side length s s must be in the range of (3,5)(3, 5) and (6,8)(6, 8) to satisfy the distance conditions.
- However, no single side length s s can satisfy both ranges simultaneously.

Conclusion:
Since the side length of the square must fit within both ranges simultaneously, and this is impossible, the given distances cannot be from a point to the vertices of a square.

The final answer is False.

Want a route through all this instead of an archive? The track puts 2,000 problems in a working order, from AMC 10 level to the IMO shortlist.

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic and difficulty added by this site.