# If \theta is an acute angle of a right triangle and Cos \theta = \frac{3}{8}, what is...

## Question:

If {eq}\theta {/eq} is an acute angle of a right triangle and {eq}Cos \theta = \frac{3}{8}, {/eq} what is the value of {eq}Cosec\theta {/eq}?

## Trigonometric Ratios:

The trigonometric ratios relate the three sides of a right-angled triangle to its angles. The six basic trigonometric ratios are sine (sin), cosine (cos), tangent (tan), secant (sec) cosecant (csc) and cotangent (cot).

If angle {eq}\theta {/eq} is an acute angle in a right-angled triangle, then {eq}\cos theta {/eq} relates the angle to the adjacent side and the opposite side to the angle. It is equal to:

• {eq}\cos \theta = \rm \dfrac{Adjacent }{Hypotenuse} {/eq}

Recall that {eq}\csc \theta = \dfrac{1}{\cos \theta} {/eq}. Therefore:

• {eq}\csc \theta = \dfrac{1}{\cos \theta} = \rm \dfrac{Hypotenuse}{Adjacent } {/eq}

Therefore, if:

• {eq}\cos \theta = \dfrac{3}{8} {/eq}, then:
• {eq}\csc \theta = \dfrac{1}{\cos \theta} = \boxed{\dfrac{8}{3}} {/eq}