Enlargement Center
1. **State the problem:** We need to determine if the point (2,9) can be the center of enlargement that maps the smaller cross centered at (4,7) to the larger cross centered at (9,4).
2. **Understand enlargement:** An enlargement with center $C=(x_c,y_c)$ and scale factor $k$ maps any point $P=(x,y)$ to $P'=(x',y')$ such that:
$$x' = x_c + k(x - x_c)$$
$$y' = y_c + k(y - y_c)$$
3. **Apply to centers:** Let the smaller center be $P=(4,7)$ and the larger center be $P'=(9,4)$, and the proposed center of enlargement be $C=(2,9)$.
4. **Set up equations:**
$$9 = 2 + k(4 - 2)$$
$$4 = 9 + k(7 - 9)$$
5. **Simplify each:**
- For $x$ coordinate:
$$9 = 2 + 2k \implies 2k = 7 \implies k = 3.5$$
- For $y$ coordinate:
$$4 = 9 + k(-2) \implies 4 - 9 = -2k \implies -5 = -2k \implies k = 2.5$$
6. **Compare scale factors:** The $x$ and $y$ calculations give different scale factors ($3.5$ vs $2.5$), which is impossible for a single enlargement.
7. **Conclusion:** Since the scale factors do not match, (2,9) cannot be the center of enlargement mapping the smaller cross to the larger cross.
**Final answer:** No, (2,9) is not the center of enlargement because the scale factors derived from the $x$ and $y$ coordinates are not equal, which violates the properties of enlargement.