The given triangle is right angle triangle with side a = 8 and b 7
Apply pythagoras theorem for the side c;
In a right-angled triangle, the square of the hypotenuse side is equal to the sum of squares of the other two sides.
Hypotenuse² = Perpendicular² + Base²
Here, perpendicular, a =8 and Base b = 7
The trignometric ratio for sec of an angle define as the ratio of the hypotenuse to the side adjacent to a given angle in a right triangle.
The trignometric ratio for cosine of angle define as the ratio of the adjacent side to the the opposite side of the angle,
Answer; a)