A Triangle's Angles

The sum of the measures of the interior angles of any triangle is 180°.

To mirror an object, make sure the "Mirror object at line" tool is selected. Then click the object to mirror, followed by the line segment.

Reflect each colored triangle about the corresponding segment.

A = (-2.18, 2.1)
B = (5.34, -0.28)
a = Segment(A, B)
C = (1.82, 4.9)
b = Segment(B, C)
c = Segment(C, A)
d = OrthogonalLine(C, a)
D = Intersect(a, d)
e = Segment(C, D)
E = Midpoint(e)
f = Line(E, a)
F = Intersect(c, f)
G = Intersect(b, f)
h = OrthogonalLine(F, a)
i = OrthogonalLine(G, a)
H = Intersect(a, h)
I = Intersect(a, i)
poly1, h_1, a_1, f_1 = Polygon(A, F, H)
poly2, g_1, c_1, f_2 = Polygon(C, F, G)
poly3, b_1, g_2, i_1 = Polygon(G, I, B)
l = Segment(F, D)
m = Segment(G, D)