OG详解-OG5 数学1 Q20

The correct answer is1128​​. The cosine of an acute angle in a right triangle is defined as the ratio of the length of the leg adjacent to the angle to the length of the hypotenuse. In the triangle shown, the length of the leg adjacent to the angle with measure x is 11 units and the length of the hypotenuse is 28 units. Therefore, the value of cosx is 1128​. Note that 11/28, .3928, .3929, 0.392, and 0.393 are examples of ways to enter a correct answer.