Answer: Side a equals 19.5 metres
Step-by-step explanation: Consider the right angled triangle as shown in the picture attached. The triangle has been drawn with angle measuring 43 degrees, side c (line AB) measuring 26.7 m and side a (line CB) is yet unknown.
A right angled triangle can be solved if at least one side and an angle are available. In this question we shall apply the trigonometric ratios since we have one angle which shall be the reference angle (43°). Also we have an hypotenuse (the side facing the right angle) and an unknown side which is the adjacent (which lies between the right angle and the reference angle).
Cos B = Adjacent/Hypotenuse
Cos 43 = a/26.7
Cos 43 x 26.7 = a
0.7314 x 26.7 = a
19.52714 = a
a ≈ 19.5 (rounded to the nearest tenth)
Therefore the length of side a equals 19.5 metres.
