Check the picture below.
we know that AL is an angle bisector, so the angle at A gets cuts into two equal halves, we also know the angle at B is 30°, so the triangle ABC is really a 30-60-90 triangle, meaning the angle at A is really a 60° angle, cut in two halves gives us 30° and 30° as you see in the picture.
if the angles at A and B, inside the triangle ABL, are equal, twin angles are only made in an isosceles by twin sides, that means that AL = BL.
Looking at the triangle ALC, we can see is also another 30-60-90 triangle, and we can just use the 30-60-90 rule to get x=CL.
Answer:
Option C is correct
Step-by-step explanation:
Given: A plane is descending onto the runway with an angle of depression of 55°. Also, it has 2.8 miles to go before landing.
To find: current altitude of the plane
Solution:
Consider the attached image.
In ΔABC,
(Alternate interior angles)
For any angle ,
= side opposite to angle/side adjacent to angle
Put
So, the current altitude of the plane is 4 miles.
