The coordinates of the vertices of the dilated figure are A'(1.25, 10), B'(7.5, 1.25), and C'(-11.25, 5).
The multiplication of a vector with a positive real number without changing its direction is called scalar multiplication.
The given triangle has the vertices A(1,8), B(6,1), and C(-9,4).
The matrix representation of the triangle ABC is,
[tex]\left[\begin{array}{ccc}1&6&-9\\8&1&4\end{array}\right][/tex]
And the scale factor is 5/2.
The matrix representation of the dilated figure can be obtained by multiplying the above matrix with 5/4.
[tex]=\dfrac{5}{4}\left[\begin{array}{ccc}1&6&-9\\8&1&4\end{array}\right]\\[/tex]
[tex]=\left[\begin{array}{ccc}\dfrac{5}{4}&\dfrac{15}{2}&\dfrac{-45}{4}\\10&\dfrac{5}{4}&5\end{array}\right]\\[/tex]
[tex]=\left[\begin{array}{ccc}1.25&7.5&-11.25\\10&1.25&5\end{array}\right][/tex]
Hence, the coordinates of the vertices of the dilated figure are A'(1.25, 10), B'(7.5, 1.25), and C'(-11.25, 5).
Learn more about dilated figures here - https://brainly.com/question/18068466
#SPJ2