Please find attached, the graph of the image of the triangle ΔKLM, after a rotation 90° counterclockwise around the origin, created using MS Excel
The steps used to find the coordinated of the vertices of the image are as follows;
The coordinates of the point (x, y) after a rotation 90° counterclockwise around, the origin is (-y, x)
Therefore, the coordinates of the vertices of the image of the triangle ΔKLM, with vertice coordinates K(-8, 3), L(-2, 3), and M(-8, 9) can be found as follows;
K(-8, 3) → R₉₀ → K'(-3, -8)
L(-2, 3) → R₉₀ → L'(-3, -2)
M(-8, 9) → R₉₀ → M'(-9, -8)
The coordinates found above can be used to graph the image of the triangle ΔKLM using MS Excel
Please find the graph of the image of the triangle ΔKLM, created with MS Excel