In a right triangle with legs a and b and hypotenuse c, a² + b² = c².

Pythagorean Theorem for an Obtuse Triangle

c² > a² + b²

c² < a² + b²

sin θ = cos (90^o – θ) or

cos θ = sin (90^o – θ)

the angle made between the observer and the horizontal when looking a an object at a lower level

the angle made between the observer and the horizontal when looking a an object at a higher level

the symbol θ which is commonly used as a variable for an angle