Use the image to answer the question. For the square pyramid, the lateral edge length, e , is 25 in., and the slant height, s , is 24 in. Find the height of the pyramid, h . Round the answer to the nearest whole number. Hint: Before finding the length of h , you will first need to find the length of r . (1 point) The height of the square pyramid is in.

2 answers

To find the height \( h \) of the square pyramid with given lateral edge length \( e = 25 \) inches and slant height \( s = 24 \) inches, we first need to determine the length of \( r \), which is half the length of the base side of the pyramid.

In a square pyramid, the relationship between the slant height \( s \), the height \( h \), and half the base side \( r \) can be expressed using the Pythagorean theorem:

\[ s^2 = h^2 + r^2 \]

From the problem, we also know the relationship between the lateral edge \( e \), the height \( h \), and half the diagonal of the base. The half diagonal \( d \) of the base can be calculated from the side length of the base, which is \( 2r \):

\[ d = \sqrt{(2r)^2 + (2r)^2} = \sqrt{8r^2} = 2\sqrt{2}r \]

The relationship involving the lateral edge \( e \) can also be expressed using the Pythagorean theorem:

\[ e^2 = h^2 + d^2 \]

Substituting for \( d \):

\[ e^2 = h^2 + (2\sqrt{2}r)^2 = h^2 + 8r^2 \]

Now we have two equations:

  1. \( s^2 = h^2 + r^2 \)
  2. \( e^2 = h^2 + 8r^2 \)

Now, let's substitute the known values:

  1. For \( s = 24 \): \[ 24^2 = h^2 + r^2 \implies 576 = h^2 + r^2 \quad (1) \]

  2. For \( e = 25 \): \[ 25^2 = h^2 + 8r^2 \implies 625 = h^2 + 8r^2 \quad (2) \]

Now we can solve these two equations simultaneously. From equation (1), we can express \( h^2 \):

\[ h^2 = 576 - r^2 \]

Now, substitute \( h^2 \) into equation (2):

\[ 625 = (576 - r^2) + 8r^2 \] \[ 625 = 576 + 7r^2 \] \[ 625 - 576 = 7r^2 \] \[ 49 = 7r^2 \implies r^2 = 7 \implies r = \sqrt{7} \]

Now substituting \( r^2 = 7 \) back into equation (1) to find \( h^2 \):

\[ h^2 = 576 - 7 \] \[ h^2 = 569 \] \[ h = \sqrt{569} \approx 23.8 \]

Rounding to the nearest whole number, the height \( h \) of the square pyramid is:

\[ \boxed{24} \text{ inches} \]

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