Question: Dilate $\triangle ABC$ with a scale factor of $3$. Enter the new coordinates.
$A = (1,2)$
$B = (3,-1)$
$C = (-4,-2)$
$A' = ( ?, )$
$B' = ( , )$
$C' = ( , )
1. **State the problem:** We need to find the coordinates of the dilated triangle $\triangle A'B'C'$ after applying a dilation with scale factor $3$ to the original triangle $\triangle ABC$ with vertices $A(1,2)$, $B(3,-1)$, and $C(-4,-2)$.
2. **Formula for dilation:** When a point $(x,y)$ is dilated from the origin by a scale factor $k$, the new coordinates $(x',y')$ are given by:
$$
(x', y') = (kx, ky)
$$
3. **Apply the formula to each vertex:**
- For $A(1,2)$:
$$
A' = (3 \times 1, 3 \times 2) = (3, 6)
$$
- For $B(3,-1)$:
$$
B' = (3 \times 3, 3 \times (-1)) = (9, -3)
$$
- For $C(-4,-2)$:
$$
C' = (3 \times (-4), 3 \times (-2)) = (-12, -6)
$$
4. **Final answer:**
$$
A' = (3, 6), \quad B' = (9, -3), \quad C' = (-12, -6)
$$
These are the coordinates of the dilated triangle $\triangle A'B'C'$ with scale factor $3$.