Since you neglected to name two of them in the question,
I'll have to list all three in order to be sure of answering it:
-- Vega . . . in Lyra
-- Altair . . . in Aquila
-- Deneb . . . in Cygnus
This stars of the winter triangle are a landmark of the winter night sky and is formed by our brightest night sky star, Sirius, the giant star, Betelgeuse, and the brightest star in Canis Minor, Procyon.
It is a reference to three bright stars that can be seen in northern hemisphere. Altair in the constellation Aquila, forms the top of the triangle. Vega in the constellation Lyra is the brightest star and is almost directly overhead. Deneb in the constellation Cygnus is the third star.
Vega
Vega is the bright star that forms the summer triangle with Deneb and Altair. It is the fifth brightest star in the night sky and is easily visible during the summer months from the northern hemisphere. Vega is part of the constellation Lyra and has been used as a navigational reference point for centuries.
Deneb is a star in the constellation Cygnus. It is part of the summer triangle. It has no specific Japanese meaning.
The third triangle number is 6.
The Arab term "Summer comes on the wind of birds refers to the the arrival of birds in the spring to signal the coming of summer, in the same way the summer triangle is a astronomical imaginary triangle that shows in the northern hemisphere at the beginning of spring into summer.
The supplementary angle of the triangle.
The three stars that make up The Summer Triangle are: Vega, Altair, and Deneb.Look below at Sources and related links to see the stars and constellations of The Summer Triangle.
Yes, it is known as a star, but it is two triangles.It is one upside down triangle on one upward triangle.
Third Star was created in 2010.
Deneb is part of the constellation Cygnus, also known as the Northern Cross. It is the brightest star in Cygnus and one of the corners of the Summer Triangle, a prominent asterism in the northern hemisphere sky.