Susan and Mark are standing at different places on a beach and watching a bird. The angles of elevation they make are 20º and 50º, respectively. If Susan and Mark are 7 kilometers apart and the bird is between them, the bird is at a height of kilometers from the ground.

The bird is 2.44km high

Step-by-step explanation:

Hello,

To solve this question, we need to understand how they are and we can only get this with a correct pictorial diagram.

See attached document for better understanding.

From the first diagram, we understand that the bird is between them and also on top of them.

Assuming Susan, Mark and the bird all form a triangle at each other and the bird at the top, we can divide the the triangle into two equal parts.

But before then, we should know that sum of angles in a triangle is equal to 180°

Therefore,

20° + 50° + b° = 180

70° + b = 180

b = 180° - 70°

b = 110°

Dividing angle b into two equal parts = 55° on each side.

See the last attached document for better illustration.

Using SOHCAHTOA, we can find the adjacent of the triangle which corresponds to the height of the bird.

We have opposite = 3.4km and we're looking for adjacent. We can use tangent of the angle to find the adjacent.

Tanθ = opposite / adjacent

Tan 55° = 3.5 / adj

Adjacent = 3.5 / tan55

Adjacent = 3.5 / 1.43

Adjacent = 2.44km

The height of the bird is 2.44km

b. 1.25 hr

step-by-step explanation:

if you have a constant speed of 60 mph, then you have a ratio between 60 mi. to 1 hr. dividing both sides by 60 we get the ratio

1 mi. to

then mult. both sides by 75 we get the ratio

75 mi. to

simplifying we get

75 mi. to

or 1.25 hr.

no

step-by-step explanation: