Re: In a right triangle PQR, X and Y are mid points of PQ and PR
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28 Jul 2025, 00:50
Given:
- Triangle $P Q R$ is a right triangle with $\(\angle Q=90^{\circ}\)$.
- $X$ and $Y$ are midpoints of $P Q$ and $P R$, respectively.
- $T$ is any point on $Q R$.
- $P Q=6$, and $Q R=8$.
We want to compare:
- Quantity A = Area of quadrilateral PXTY
- Quantity B = 12
Let's analyze the problem step by step.
Step 1: Define coordinates
Set $Q$ at the origin $(0,0)$.
- Since $P Q$ is vertical (right angle at $Q$ ), set $P=(0,6)$ because $P Q=6$.
- Since $Q R$ is horizontal, let $R=(8,0)$ because $Q R=8$.
Step 2: Coordinates of midpoints and T
- $X$ is midpoint of $P Q$ :
$$
\(X=\left(\frac{0+0}{2}, \frac{6+0}{2}\right)=(0,3)\)
$$
- $Y$ is midpoint of $P R$ :
Since $P=(0,6)$ and $R=(8,0)$,
$$
\(Y=\left(\frac{0+8}{2}, \frac{6+0}{2}\right)=(4,3)\)
$$
- $T$ is any point on $Q R$. Let
$$
\(T=(t, 0) \quad \text { where } 0 \leq t \leq 8\)
$$
Step 3: Calculate the area of quadrilateral $P X T Y$
The quadrilateral vertices are $P(0,6), X(0,3), T(t, 0)$, and $Y(4,3)$.
Use the shoelace formula to find the area:
$$
\(\text { Area }=\frac{1}{2}\left|x_1 y_2+x_2 y_3+x_3 y_4+x_4 y_1-\left(y_1 x_2+y_2 x_3+y_3 x_4+y_4 x_1\right)\right|\)
$$
Plug in the points in order $P \rightarrow X \rightarrow T \rightarrow Y$ :
$$
\(\begin{aligned}
& x_1 y_2=0 \times 3=0 \\
& x_2 y_3=0 \times 0=0 \\
& x_3 y_4=t \times 3=3 t \\
& x_4 y_1=4 \times 6=24 \\
& \sum=0+0+3 t+24=3 t+24 \\
& y_1 x_2=6 \times 0=0 \\
& y_2 x_3=3 \times t=3 t \\
& y_3 x_4=0 \times 4=0 \\
& y_4 x_1=3 \times 0=0 \\
& \sum=0+3 t+0+0=3 t
\end{aligned}\)
$$
So the area is:
$$
\(\text { Area }=\frac{1}{2}|(3 t+24)-3 t|=\frac{1}{2} \times 24=12\)
$$
Step 4: Conclusion
The area of quadrilateral $P X T Y$ is 12 regardless of the location of $T$ on $Q R$.
Final answer:
- Quantity A = 12
- Quantity B = 12
Quantity A = Quantity B