Answer:
The scale factor is equal to
![3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/j9nm6zke2w2yvzr90sfzxxfsj5zwj66fau.png)
Explanation:
we know that
If two figures are similar, then the ratio of its areas is equal to the scale factor squared
Let
z-----> the scale factor
x-----> the area of the image
y----> the area of the original garden
so
![z^(2)=(x)/(y)](https://img.qammunity.org/2020/formulas/mathematics/high-school/bsr5zpx86e0gikgp398wuhrw2lup269tnz.png)
we have
![x=900\ ft^(2)](https://img.qammunity.org/2020/formulas/mathematics/high-school/8gjp716tu7qpreinkfy1n3srew6g46ried.png)
![y=100\ ft^(2)](https://img.qammunity.org/2020/formulas/mathematics/high-school/brp0r7eoywbq2qvy9g0821v4fjiot1wk9o.png)
substitute and solve for z
![z^(2)=(900)/(100)](https://img.qammunity.org/2020/formulas/mathematics/high-school/ykdu1migpifnyse3cxo37geikgpw88lojb.png)
![z^(2)=9](https://img.qammunity.org/2020/formulas/mathematics/high-school/g5r1tfh6060413c3am5sh4f7x402jh6a8k.png)
------> scale factor