In an isosceles triangle, the height that is drawn from the apex divides the base of the triangle into two equal parts and the apex angle into two equal angles. The two angles adjacent to the base are called the base angles, while the angle opposite the base is called the vertex angle. Because the legs are of equal length, the base angles are also identical. Therefore, depending on the side and angle measurements, your isosceles triangle could be an acute, obtuse, right, or equilateral triangle as well. Stack Exchange Network Stack Exchange network consists of 176 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. To find the perimeter of the triangle we just have to add up all the sides of the triangle. Similarly, in triangle PQR, PQ = PR. Mathematics Having at least two equal sides: an isosceles triangle. A right isosceles triangle is a special triangle where the base angles are \(45 ^\circ\) and the base is also the hypotenuse. isosceles triangle (plural isosceles triangles) A triangle having at least two sides equalUsage notes []. isosceles triangle synonyms, isosceles triangle pronunciation, isosceles triangle translation, English dictionary definition of isosceles triangle. An isosceles triangle has two sides of equal length. Also, the angles opposite these equal sides are equal. See more. 3. A perpendicular bisector of the base forms an altitude of the triangle as shown on the right. The sides and angles of the triangle could vary. The isosceles triangle is a type of triangle, which has two sides with the same length. That means side AD opposite angle α is shorter than side AB opposite the larger angle β. An isosceles triangle is a triangle that has (at least) two equal side lengths. (a) 12.90 cm (b) 13.28 cm (c) 19.36 cm (d) 38.72 cm 4. An isosceles triangle ABC is constructed with equal sides AB = AC. Isosceles triangles are very helpful in determining unknown angles. An Isosceles Triangle has the Following Properties: It has two sides of equal length. The formula to find the area of isosceles triangle or any other triangle is: ½ × base × height. Noun []. This fact is the content of the isosceles triangle theorem, which was known by Euclid. Isosceles triangle: A triangle with at least two congruent sides. A clear concept of what is an isosceles triangle and formula derivation for area of isosceles triangle and perimeter of isosceles triangle. Calculates the other elements of an isosceles triangle from the selected elements. Therefore, = / −, = / − / , and so, in particular, < . Two sides of isosceles right triangle are equal and we assume the equal sides to be the base and height of the triangle. If x is increasing at the rate of 4 in/min., at what rate is the triangle's a) perimeter changing b) … The angles opposite to equal sides are equal in measure. Draw all points X such that true that BCX triangle is an isosceles and triangle ABX is isosceles with the base AB. Define isosceles triangle. The two equal sides are marked with lines and the two equal angles are opposite these sides. isosceles isosceles triangle adj. If all three side lengths are equal, the triangle is also equilateral. The figure shows an isosceles triangle ABC with