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Recall the definition of tangent.
≈ 9.23 ft
We are given that Austin is standing on the high dive at the local pool and that two of his friends are in the water. We also know that one friend is 5 feet beyond the other one. Let y represent the horizontal distance from the friend that is nearer to Austin to the edge of the pool.
We are also given the angles of depression to each of Austin's friends. Since the angle of depression is always congruent to the corresponding angle of elevation, we can say that the angles of elevations are 30^(∘) and 40^(∘) respectively.
As we are asked to evaluate how tall the platform is, let x represent this height. Notice that we have two right triangles in our diagram.
(I):LHS * y=RHS* y
(I):Rearrange equation
(II):x= ytan40^(∘)
(II):LHS * (5+y)=RHS* (5+y)
(II):Distribute tan30^(∘)
(II):LHS-ytan30^(∘)=RHS-ytan30^(∘)
(II):Factor out y
(II):.LHS /(tan40^(∘)-tan30^(∘)).=.RHS /(tan40^(∘)-tan30^(∘)).
(II):Rearrange equation
(II):Use a calculator
(II):Round to nearest integer
(I):y= 11
(I):Use a calculator
(I):Round to 2 decimal place(s)