We are Given:_______________________________________________
ΔABC right angled at B
BC = 8
AC = 20
Part A:_____________________________________________________
Finding the length of AB
From the Pythagoras theorem, we know that:
AC² = BC² + AB²
replacing the given values
(20)² = (8)² + AB²
400 = 64 + AB²
AB² = 336 [subtracting 64 from both sides]
AB = 18.3 [taking the square root of both sides]
Part B:_____________________________________________________
Finding Sin(A)
we know that Sin(θ) = Opposite / Hypotenuse
The side opposite to ∠A is BC and The hypotenuse is AC
So, Sin(A) = BC / AC
Sin(A) = 8/20 [plugging the values]
Sin(A) = 2/5
Part C:_____________________________________________________
Finding Cos(A)
We know that Cos(θ) = Adjacent / Hypotenuse
The Side adjacent to ∠A is AB and the hypotenuse is AC
So, Cos(A) = AB / AC
Cos(A) = 18.3/20 [plugging the values]
Cos(A) = 183 / 200
Part D:_____________________________________________________
Finding Tan(A)
We know that Tan(θ) = Opposite / Adjacent
Since BC is opposite and AB is adjacent to ∠A
Tan(A) = BC / AB
Tan(A) = 8 / 18.3 [plugging the values]
Tan(A) = 80 / 183