The golden rectangle ratio: 1:(1 + the square root of 5) over 2 or about 1.618
5 cm
when golden rectangle constructed?
If you mean the golden rectangle then each of its 4 interior angles measures 90 degrees but if you mean an equilateral triangle then each of its 3 interior angles measures 60 degrees
phi is incorperated into the golden rectangle, because if you divide the longer side of the golden rectangle by the shorter sid, the answer will be phi.(1.168...)
Euclid was the one to construct the golden rectangle
A golden rectangle is a rectangle whose side lengths are in the golden ratio, approximately 1:1.618. A 3x5 card has side lengths of 3 inches by 5 inches, which do not match the golden ratio. Therefore, a 3x5 card is not a golden rectangle.
Each angle of a rectangle measures 90 degrees.
true
15 (it is actually really close to 15 and a half)
No, there's no golden pentagon.
conclusion
The Golden Rectangle is a geometrical figure whose side lengths are in the golden ratio. It can be made with only a compass and a straight edge.