The common formula for the area of a right-angled triangle is S= 1/2ab (where a and b are the lengths of two right-angled sides of the right-angled triangle respectively). A right triangle is a geometric figure with a right angle. There are two kinds of right-angled triangles: ordinary right-angled triangles and isosceles right-angled triangles. It conforms to Pythagorean theorem and has some special properties and judgment methods.

trait

1, the sum of squares of two right angles of a right triangle is equal to the square of the hypotenuse. ∠ BAC = 90, then AB? +AC？ =BC？ Pythagorean theorem

2. In a right triangle, two acute angles are complementary. If ∠ BAC = 90, ∠ B+∠ C = 90.

3. In a right triangle, the median line on the hypotenuse is equal to half of the hypotenuse (that is, the outer center of the right triangle is located at the midpoint of the hypotenuse, and the radius of the circumscribed circle R=C/2). This property is called the hypotenuse midline theorem of right triangle.