Secant Formula
When talking about any rightangled triangle, there are three sides that are, hypotenuse, perpendicular, and height. The side which is the largest one and is on the side which is on the opposite to the right angle is the hypotenuse. When the length of the hypotenuse is divided by the length of the adjacent side, it gives the secant of the angle, of the rightangled triangle. Secant is denoted as 'sec'. Secant formula is derived out from the inverse cosine (cos) ratio. The secant function is the reciprocal of the cosine function, thus, the secant function goes to infinity whenever the cosine function is equal to zero (0). The secant formula along with solved examples is explained below.
What Is a Secant Formula?
The secant function of a right triangle is its hypotenuse divided by its base. Thus, the secant formula of a given triangle can be expressed as,
sec θ = H/B
Where,
 B = Base
 H = hypotenuse
Also, secant is reciprocal of cos,i.e.,
sec θ = (1/cosθ)
Let us see the applications of the secant formula in the below solved examples.
Solved Examples Using Secant Formula

Example 1: Find the side of a rightangled triangle whose hypotenuse is 14 units and base angle with the side is 60 degrees.
Solution
To find:
Side (B)
θ = 60 degree
H = 14 unitsUsing the secant formula,
secθ = H/B
sec60 =14/B
2 = 14/B
B = 14/2
B = 7
Answer: The base side of a rightangle triangle is 7 Units.

Example 2: Find sec θ using the secant formula if hypotenuse = 4.9 units, the base of the triangle = 4 units, and perpendicular = 2.8 units.
Solution
To find: sec θ
Given: P = 2.8, B = 4, and H = 4.9
Using the secant formula,
secθ = H/B
secθ = 4.9/4
secθ = 1.225
Answer: sec θ is 1.225