Brahmagupta is widely regarded as the father of Indian geometry for his contributions to the field, including his work on the Pythagorean theorem and his development of the cyclic quadrilateral theorem.

Euler's theorem states that the sum of the interior angles of a triangle is always 180 degrees. This theorem is named after Leonhard Euler, who first proved it in the 18th century.

Brahmagupta developed the concept of the cyclic quadrilateral, which is a quadrilateral whose vertices lie on a circle. He also developed a formula for the area of a cyclic quadrilateral.

Heron's formula states that the area of a triangle is equal to half the product of its base and height. This formula is named after Heron of Alexandria, who first discovered it in the 1st century AD.

Brahmagupta developed the concept of the Brahmagupta quadrilateral, which is a quadrilateral whose diagonals are perpendicular to each other. He also developed a formula for the area of a Brahmagupta quadrilateral.

The Pythagorean theorem states that the sum of the squares of the two shorter sides of a right triangle is equal to the square of the hypotenuse. This theorem is named after Pythagoras, who first discovered it in the 6th century BC.

Bhaskara II developed the concept of the Bhaskara circle, which is a circle that passes through the three vertices of a triangle and is tangent to the incircle of the triangle.

The sine rule states that the area of a triangle is equal to half the product of its two sides and the sine of the angle between them. This rule is named after the sine function, which is used to calculate the sine of an angle.

Brahmagupta developed the concept of Brahmagupta's formula, which is a formula for finding the area of a cyclic quadrilateral.

Brahmagupta's theorem states that the sum of the squares of the two diagonals of a parallelogram is equal to the sum of the squares of its four sides. This theorem is named after Brahmagupta, who first discovered it in the 7th century AD.

Bhaskara II developed the concept of Bhaskara's formula, which is a formula for finding the area of a triangle.

Heron's formula states that the area of a triangle is equal to half the product of its base and height. This formula is named after Heron of Alexandria, who first discovered it in the 1st century AD.

Brahmagupta developed the concept of the Brahmagupta quadrilateral, which is a quadrilateral whose diagonals are perpendicular to each other. He also developed a formula for the area of a Brahmagupta quadrilateral.

The Pythagorean theorem states that the sum of the squares of the two shorter sides of a right triangle is equal to the square of the hypotenuse. This theorem is named after Pythagoras, who first discovered it in the 6th century BC.

Bhaskara II developed the concept of the Bhaskara circle, which is a circle that passes through the three vertices of a triangle and is tangent to the incircle of the triangle.