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.
The menstrual cycle is the time from the first day of one period to the first day of the next. A normal menstrual cycle can be as short as 21 days or longer than 35 days. For most women, it lasts 25 - 30 days. But it's common for your cycle to vary from month to month.Here are the basics: 1  You have two ovaries.here's no way to know exactly when you'll get your first period. One day, you'll begin to bleed from your vagina, and that's your period. It means that your body is healthy and normal. Most girls have their first period when they're between 9 and 15 years old.