Answer:
EF is 4 units.
Step-by-step explanation:
It is given that the two triangles [tex]\trianlge ABC, \triangle EDF[/tex] are congruent to each other i.e.
[tex]\trianlge ABC \cong \triangle EDF[/tex]
Coordinates are given as:
A(-1,1)
B(2,4)
C(3,1)
As per the property of congruence, all the corresponding sides and angles of the two triangles are equal to each other.
i.e. AB = ED
BC = DF
AC = EF
We are given with the coordinates of points A, B and C here from which we can easily calculate the side AC using the distance formula.
[tex]Distance = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
Where [tex](x_1,y_1), (x_2,y_2)[/tex] are the coordinates of the two points whose distance is to be calculated.
So,
[tex]AC = \sqrt{(3-(-1))^2+(1-1)^2}\\\Rightarrow AC = \sqrt{4^2}\\\Rightarrow AC = 4\ units[/tex]
Hence, AC = EF = 4 units