G.78 right, obtuse, and acute-angled triangles

I.def.21

A right-angled triangle has a right angle, an obtuse-angled triangle has an obtuse angle, and an acute-angled triangle has three acute angles.
triangle_angles_def

Dependency Graph

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Required for

G.79, G.80, G.91, G.92, G.93, G.94, G.95, G.97, G.114, G.116, G.143, G.144, G.145, G.162, G.163, G.164, G.218, G.223, G.237, G.240, G.241, G.243, G.244, G.385, G.390, G.396, G.397, G.398, G.399, G.400, G.401, G.402, G.403, G.404, G.405, G.406, G.407, G.408, G.409, G.410, G.411, G.412, G.413, G.414, G.415, G.416, G.417, G.418, G.419, G.420, G.421, G.423, G.425, G.427, G.431, G.433, G.434, G.435, G.436, G.437, G.438, G.439, G.440, G.441, G.442, G.443, G.444, G.445, G.446, G.447, G.448, G.449, G.450, G.451, G.452, G.453, G.457, G.458, G.459, G.460, G.461, G.462, G.463, G.464, G.465, G.466, G.467, G.468, G.470, G.472, G.474, G.476, G.477, G.478, G.479, G.480, G.481, G.482, G.483, G.484, G.485, G.486, G.487, G.488, G.489, G.490, G.491, G.492, G.493, G.494, G.495, G.496, G.497, G.498, G.499, G.500, G.528, G.545, G.546, G.561, G.563, G.565, G.570, G.571, G.572, G.573, G.577, G.578, G.584, G.589, G.590, G.592, G.594, G.595, G.597, G.600, G.601