Mathematics Menu  Engineering Calculators
Triangle (Trigonometry) Solutions Calculators
The sides of the rightangled triangle are designated a and b and the hypotenuse, c. The angles opposite each of these sides are designated A and B, respectively. Angle C, opposite the hypotenuse c is the right angle, and is therefore always one of the known quantities. 
Sides and Angles Known 
Formulas for Sides and Angles to be Found 
Side a, side b 

tan A = a/b 
B = 90° − A 
Side a, hypotenuse c 

sin A = a/c 
B = 90° − A 
Side b, hypotenuse c 

sin B = b/c 
A = 90° − B 
Hypotenuse c, angle B 
b = c × sin B 
a = c × cos B 
A = 90° − B 
Hypotenuse c, angle A 
b = c × cos A 
a = c × sin A 
B = 90° − A 
Side b, angle B 

a = b × cot B 
A = 90° − B 
Side b, angle A 

a = b × tan A 
B = 90° − A 
Side a, angle B 

b = a × tan B 
A = 90° − B 
Side a, angle A 

b = a × cot A 
B = 90° − A 
