McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
Standardized Test Practice

Exercise 13 Page 711

Practice makes perfect
a Let's begin with recalling the Geometric Mean Altitude Theorem.

The altitude drawn to the hypotenuse of a right triangle separates the hypotenuse into two segments. The length of this altitude is the geometric mean between the lengths of these two segments.

x/h=h/y or h=sqrt(x*y) Now, let's take a look at the given picture.

Using the theorem we recalled at the beginning, we can write an equation. x=sqrt(8*12.5) Now let's solve the equation.
x=sqrt(8*12.5)
x=sqrt(100)
x=10
The value of x is 10.
b Let's begin with recalling the Pythagorean Theorem.

In a right triangle, the sum of the squares of the lengths of the legs is equal to the square of the length of the hypotenuse.

a^2+ b^2= c^2 Now, let's look at the given picture.

Since an altitude in a triangle divides this triangle into two right triangles, we can use the Pythagorean Theorem to evaluate the value of y.
10^2+ 8^2= y^2
100+64=y^2
164=y^2
y^2=164
Next we will take a square root of both sides of the equation. Notice that since y represents the side length, we will consider only the positive case when taking a square root of y^2.
y^2=164
sqrt(y^2)=sqrt(164)
y=sqrt(164)
y=12.8062...
y≈ 12.8
The value of y is approximately 12.8.
c Again, let's begin with recalling the Pythagorean Theorem.

In a right triangle, the sum of the squares of the lengths of the legs is equal to the square of the length of the hypotenuse.

a^2+ b^2= c^2 Next we will look at the given picture for the last time.

Having in mind that an altitude in a triangle divides this triangle into two right triangles, we can again use the Pythagorean Theorem to evaluate the value of z.
10^2+ 12.5^2= z^2
100+156.25=z^2
256.25=z^2
z^2=256.25
Next we will take a square root of both sides of the equation. Notice that since z represents the side length, we will consider only positive case when taking a square root of z^2.
z^2=256.25
sqrt(z^2)=sqrt(256.25)
z=sqrt(256.25)
z=16.0078...
z≈ 16
The value of z is approximately 16.