Triangle Enlargement
1. **State the problem:**
We have triangle PQR with vertices P(3,4), Q(5,3), and R(4,1).
We want to find the image of this triangle after an enlargement centered at the origin with scale factors (i) $k=2$ and (ii) $k=-\frac{1}{2}$.
2. **Formula for enlargement:**
If a point has coordinates $(x,y)$, its image after enlargement with center at the origin and scale factor $k$ is given by:
$$ (x', y') = (kx, ky) $$
3. **Apply the formula for (i) $k=2$:**
- For $P(3,4)$: $P' = (2 \times 3, 2 \times 4) = (6, 8)$
- For $Q(5,3)$: $Q' = (2 \times 5, 2 \times 3) = (10, 6)$
- For $R(4,1)$: $R' = (2 \times 4, 2 \times 1) = (8, 2)$
4. **Apply the formula for (ii) $k=-\frac{1}{2}$:**
- For $P(3,4)$: $P' = \left(-\frac{1}{2} \times 3, -\frac{1}{2} \times 4\right) = \left(-\frac{3}{2}, -2\right)$
- For $Q(5,3)$: $Q' = \left(-\frac{1}{2} \times 5, -\frac{1}{2} \times 3\right) = \left(-\frac{5}{2}, -\frac{3}{2}\right)$
- For $R(4,1)$: $R' = \left(-\frac{1}{2} \times 4, -\frac{1}{2} \times 1\right) = (-2, -\frac{1}{2})$
5. **Summary:**
- For $k=2$, the image vertices are $P'(6,8)$, $Q'(10,6)$, $R'(8,2)$.
- For $k=-\frac{1}{2}$, the image vertices are $P'\left(-\frac{3}{2}, -2\right)$, $Q'\left(-\frac{5}{2}, -\frac{3}{2}\right)$, $R'\left(-2, -\frac{1}{2}\right)$.
This completes the enlargement transformations for both scale factors.