In Euclidean geometry the sum of the angles of a triangle is equal to two right angles (180Â°). If all three angles of a triangle are equal, the triangle is called equilateral. An isosceles triangle has two equal angles. A scalene triangle is one in which all three angles are different.
A period, or menstruation, is the shedding of the endometrium-the uterine lining. Menstruation is also known as menses. All female humans, as well as some other female mammals, have regular periods during their reproductive age. Menstruation which includes bleeding from the vagina is found mainly among humans and similar animals, such as primates.
But the monthly cycle is exactly that â a process that takes about a month. A normal menstrual cycle for girls and teens ranges from 21 to 45 days. At most, only a week of the cycle involves menstrual fluid exiting the body. A normal period lasts from 2 to 7 days.