Answer – The missing opposite side in the given right-angled triangle can be calculated by employing the trigonometric ratio tangent for the 40° angle. The opposite side is found to be ≅ 10 cm.
Explanation:
We begin by drawing a triangle and labeling all its angles and sides based on the given information. We know that the side of length 12 is adjacent to the 40° angle. Therefore, it must be between this angle and the right angle as shown below. Let’s call the unknown opposite side x.
Since we know the adjacent side of the triangle, the most suitable trigonometric ratio for calculating x is tangent. The formula for this is:
Tan θ = Opposite side / Adjacent side
On providing the value of θ as 40 and adjacent side length as 12, we get:
Tan 40 = x / 12
Finally, to calculate the unknown opposite side x, we cross-multiply and arrive at the following equation:
x = Tan 40 × 12
x = 0.8390 × 12
x = 10.06 ≅ 10
Therefore, the length of the missing side of the given triangle is 10.