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.

1 answer

To find the height \( h \) of the square pyramid, we need to first determine the radius \( r \) of the base (which is half the length of the square's diagonal), and then we can use the Pythagorean theorem in the right triangle formed by the height \( h \), the radius \( r \), and the slant height \( s \).

  1. Finding the radius \( r \):

    Since we know the lateral edge length \( e \) (which is equal to \( 25 \) in) and the slant height \( s \) (which is equal to \( 24 \) in), we can create a right triangle that includes the slant height, the height of the pyramid, and a segment from the apex of the pyramid to the midpoint of a base edge.

    In this triangle:

    • The lateral edge \( e \) acts as the hypotenuse.
    • The slant height \( s \) is the side opposite to the angle from the apex to the midpoint of the base edge.
    • The radius \( r \) is half the length of the base edge.
  2. Using the Pythagorean Theorem:

    In the triangle formed: \[ e^2 = h^2 + r^2 \] We also have: \[ s^2 = h^2 + r^2 \]

    Using the slant height \( s \): \[ r = \sqrt{s^2 - h^2} \] We need expressions for both \( h \) and \( r \).

  3. Finding the height \( h \):

    From the relationship \( r = \sqrt{e^2 - h^2} \) and with \( e = 25 \), we can say: \[ 25^2 = h^2 + r^2 \] \[ 625 = h^2 + r^2 \]

    To express \( r \) in terms of \( s \), we also have: \[ 24^2 = h^2 + r^2 \] \[ 576 = h^2 + r^2 \]

  4. Setting equations for \( h \):

    We have two equations now, and we can solve these to find \( h \): \[ 625 = h^2 + r^2 \quad (1) \] \[ 576 = h^2 + r^2 \quad (2) \]

    This implies: \[ h^2 + r^2 = 625 \] \[ h^2 + r^2 = 576 \]

    From equation (1) and (2), we now focus on using the lateral edge: \[ e = \sqrt{h^2 + r^2} \] Using the Law of Cosines (where \( L = 25 \)): \[ 25^2 = h^2 + [(24^2 - h^2)] \] \[ 645 - (576 - h^2) = 625 \] Then plug in: \[ h^2 = 625 - r^2 \]

To find numerical values, we need to start systematically to isolate \( h \).

If we assume \( r \) is equal to multiple equations in our calculations, but using \( (e^2 - s^2) = r^2 \): Taking trial errors: \[ e^2 = r^2 + h^2 \rightarrow h = e^2 - s^2 = \sqrt{625 - 576} = \sqrt{49} = 7. \]

Thus, calculate to find ( r: r^2 = 625 - (7^2) \rightarrow 625 - 49 = 576 ] Thus, we find: \[ h = \sqrt{576 - 24^2} \]

Finally, we compute the height \( h \) = 7 in, directly rounded from our initial trial error relationships.

Therefore, the height of the square pyramid is \( 7 \) in.