McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
Study Guide and Review
Continue to next subchapter

Exercise 14 Page 703

Analyze what lengths you are given and use either the Geometric Mean Altitude Theorem or the Geometric Mean Leg Theorem to write a proportion.

x=2sqrt(13)≈ 7.2
y=3sqrt(13)≈ 10.8
z=6

Practice makes perfect

Let's analyze the given right triangle so that we may find the values of x, y, and z.

We know the length of both segments of the hypotenuse and expressions for other sides of a triangle. Therefore, we can use the Geometric Mean Altitude Theorem or the Geometric Mean Leg Theorem to write a proportion.

We will find x, y, and z one at a time.

Finding z

Let's compare the theorems to the expressions in our figure. We will use the first expression which is the Geometric Mean Altitude Theorem. In our case, 4 is the length of a partial segment of the hypotenuse, 9 is the length of the other segment of the hypotenuse, and z is the length of the height of the triangle. d/h=h/e ⇔ 4/z=z/9 Now we can use the Cross Product Property to find the value of z.
4/z=z/9
z* z = 4* 9
Solve for z
z^2=4 * 9
z^2=36
z=sqrt(36)
z=6
Since a negative side length does not make sense, we only need to consider positive solutions. Therefore, we found that z=6.

Finding y

We've found that z=6. Let's add this information to our diagram.

Now, let's use the second expression from our figure which is the Geometric Mean Leg Theorem. We know that, 4+9= 13 is the length of the hypotenuse, 9 is the length of a partial segment of the hypotenuse, and y is the length of the leg that is adjacent to the partial segment. c/a=a/e ⇔ 13/y=y/9 Once again, we can use the Cross Product Property to find the value of y.
13/y=y/9
y * y=13 * 9
Solve for y
y^2=13 * 9
y^2=117
y=sqrt(117)
y=sqrt(9 * 13)
y=sqrt(9)*sqrt(13)
y=3sqrt(13)
y=10.81665...
y≈ 10.8
Since a negative side length does not make sense, we only need to consider positive solutions. Therefore, we found that y=3sqrt(13)≈ 10.8.

Finding x

Let's add obtained information to the diagram.

Finally, we can use the third expression from the figure which is the Geometric Mean Leg Theorem. We already know that 4 is the length of one segment of the hypotenuse, 13 is the length of the hypotenuse, and x is the length of the shorter leg of the triangle. c/b=b/d ⇔ 13/x=x/4 Once again, we will use the Cross Product Property to find the value of x.
13/x=x/4
x* x = 13* 4
Solve for x
x^2=13* 4
x=sqrt(13* 4)
x=sqrt(13)*sqrt(4)
x=sqrt(13)* 2
x=2sqrt(13)
x=7.21110...
x≈ 7.2