1. Diketahar sebuah segirigo \( P Q R \) dengan titik \( P(2,1), Q(5,4), Q(-1,3) \) Gambarlah puda bidang koordinat kartesius dengan menggunakan transformasl. Tentukan bayangan legitiga \( P Q R \)

We are given a triangle with vertices \[ P(2,1),\quad Q(5,4),\quad R(-1,3) \] and asked to “draw the figure on the Cartesian plane using a transformation” and “determine the image of the triangle.” In many problems the transformation indicated is a reflection (that is, finding the mirror‐image of the figure). Here we will assume the reflection is taken in the \(y\)-axis. (In a reflection in the \(y\)-axis the rule is \[ (x,y)\longrightarrow (-x,y) \] ) Below is the step‑by‑step solution. 1. **Write the original coordinates.** The triangle \(PQR\) has vertices \[ P(2,1),\quad Q(5,4),\quad R(-1,3). \] 2. **State the transformation rule.** Since we reflect in the \(y\)-axis, the rule is \[ (x,y)\rightarrow (-x,y). \] 3. **Apply the transformation to each vertex.** - For \(P(2,1)\): \[ P' = (-2,\,1). \] - For \(Q(5,4)\): \[ Q' = (-5,\,4). \] - For \(R(-1,3)\): \[ R' = (1,\,3). \] 4. **State the coordinates of the image.** The image of triangle \(PQR\) after reflection in the \(y\)-axis has vertices \[ P'(-2,1),\quad Q'(-5,4),\quad R'(1,3). \] 5. **How to draw on the Cartesian plane.** - Draw the \(x\)‑axis and \(y\)‑axis. - Plot the original points: - \(P(2,1)\) in quadrant I, - \(Q(5,4)\) in quadrant I, - \(R(-1,3)\) in quadrant II. - Connect these points to form the triangle \(PQR\). - Then, plot the reflected points: - \(P'(-2,1)\) in quadrant II, - \(Q'(-5,4)\) in quadrant II, - \(R'(1,3)\) in quadrant I. - Join these reflected points to form the reflected triangle \(P'Q'R'\). Thus, the image of triangle \(PQR\) under reflection in the \(y\)-axis is the triangle with vertices \[ P'(-2,1),\quad Q'(-5,4),\quad R'(1,3). \]