Algenib and Algol form with γ Andromedæ, a right-angled triangle.
Figure 61 represents a right-angled triangle, A and B forming a right angle.
In a right-angled triangle, of which one of the other angles is 45°, the remaining angle is also 45°.
In place of "right-angled triangle" modern writers speak of "right triangle," and so for the obtuse and acute triangles.
Fold number one back toward the right, making at the fold a right-angled triangle.
Shall I prove to you that the sum of the angles of a right-angled triangle is equal to two right angles?
The glass shows two small stars forming a right-angled triangle with it.
Lines connecting the stars γ Andromedæ, Algol, and α Persei form a right-angled triangle.
It was now more sharply defined than ever, a right-angled triangle of almost mathematical precision.
The profile of these cribs was that of a right-angled triangle, the slanting side up stream.