The similarity ratio of ΔABC to ΔDEF = 2 : 1.
Solution:
The image attached below.
Given ΔABC to ΔDEF are similar.
To find the ratio of similarity triangle ABC and triangle DEF.
In ΔABC: AC = 4 and CB = 5
In ΔDEF: DF = 2, EF = ?
Let us first find the length of EF.
We know that, If two triangles are similar, then the corresponding sides are proportional.
⇒
![(AC)/(DF) =(BC)/(EF)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/o4e4rwu2dpuwsiz7mqgsxi6rtyifqkqpy3.png)
⇒
![(4)/(2) =(5)/(EF)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/zcg7mkf4x3ez3ic0g80ob3czggitlk5hj4.png)
⇒
![4EF=5*2](https://img.qammunity.org/2021/formulas/mathematics/middle-school/t9xl0cwopqb44pj9z1fdei3ejv6vl02gxx.png)
⇒
![EF=(5* 2)/(4)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/crg221addddo3j4b0cfhpv383uj7p08n08.png)
⇒
![EF=(5)/(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/q38hooeoikim45e130dnhcdjxtv1of3e0n.png)
Ratio of ΔABC to ΔDEF =
![(AC)/(DF) =(4)/(2)=(2)/(1)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/1qhhwflpkjzefwbhnr5wi2fl2zysxdbenm.png)
Similarly, ratio of ΔABC to ΔDEF =
![(BC)/(EF) =(5)/((5)/(2))=(2)/(1)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/bnovg4z7dtqzd5ucblbdkqr41x1ki6w8r7.png)
Hence, the similarity ratio of ΔABC to ΔDEF = 2 : 1.