Question:easy

If the distance between the points (4, p) and (1, 0) is 5, then p is equal to :

Show Hint

The coordinates form a right-angled triangle where the hypotenuse is the distance (5) and the horizontal side is the \(x\)-difference (\(|4 - 1| = 3\)).
Using the standard \((3, 4, 5)\) Pythagorean triple, the vertical side (which is the \(y\)-difference \(|p - 0|\)) must be equal to 4:
\[ |p| = 4 \implies p = \pm 4 \]
This geometric approach is extremely quick and visual!
Updated On: Jul 7, 2026
  • \(\pm\) 4
  • 4
  • - 4
  • 0
Show Solution

The Correct Option is A

Solution and Explanation

Step 1: Picture the two points as two corners of a right triangle instead of jumping into the distance formula.
The points are $(4, p)$ and $(1, 0)$. Moving from $(1, 0)$ to $(4, p)$, we move 3 units horizontally (since $4 - 1 = 3$) and $p$ units vertically. These two movements are perpendicular to each other, so they form the two legs of a right angled triangle, with the straight line distance between the points as the hypotenuse.

Step 2: Apply the Pythagorean theorem directly to this triangle.
For a right triangle, (horizontal leg)$^2$ + (vertical leg)$^2$ = (hypotenuse)$^2$. Here the hypotenuse is the given distance, 5.
\[ 3^2 + p^2 = 5^2 \]

Step 3: Solve this equation for $p$.
\[ 9 + p^2 = 25 \]
\[ p^2 = 25 - 9 = 16 \]
\[ p = \pm 4 \]

Step 4: Sanity check using the well known 3-4-5 triangle.
A right triangle with legs 3 and 4 always has hypotenuse 5, which is exactly the classic 3-4-5 Pythagorean triple. Since our horizontal leg is 3 and the hypotenuse is 5, the vertical leg has to be 4, confirming $p = \pm 4$.

Final Answer:
The value of $p$ is $\pm 4$, which corresponds to option (A). \[ \boxed{p = \pm 4} \]
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