Shall I prove to you that the sum of the angles of a right-angled triangle is equal to two right angles?
Algenib and Algol form with γ Andromedæ, a right-angled triangle.
In a right-angled triangle, the sum of the squares of the base and the perpendicular equals the square of the hypotenuse.
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.
Lines connecting the stars γ Andromedæ, Algol, and α Persei form a right-angled triangle.
Another simile likens it to a right-angled triangle, with the Bitter Root Range as its base.
It was now more sharply defined than ever, a right-angled triangle of almost mathematical precision.
In a right-angled triangle, of which one of the other angles is 45°, the remaining angle is also 45°.
A right-angled triangle is one in which two of the sides are at a right angle one to the other.