Question

Use the image to answer the question.

An illustration shows a square pyramid with labeled parts. The left, front, and right faces of the pyramid and base are visible. The back face is not visible, but its position is indicated by a dashed line. The back base edge is not visible, but its position is indicated by a dashed line. The left base edge is labeled a. The back left lateral edge is labeled e. A dotted line extends from the interior of the vertex straight down to the center of the base and is labeled h. A right angle is indicated where the dotted height line meets the base. Another dotted line extends from the center of the base where the height line meets to the center of the right base edge and is labeled r. A dotted line extends from the right base edge straight up the center of the right face of the prism and meets the height line at the vertex. The dotted slant height line is labeled s.

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.
Remaining Attempts : 3
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1 answer

To find the height \( h \) of the square pyramid, we can use the relationship between the lateral edge, the slant height, and the height of the pyramid.

  1. Understand the dimensions: You have a square pyramid where:

    • Lateral edge length \( e = 25 , \text{in} \)
    • Slant height \( s = 24 , \text{in} \)
  2. Find the length of \( r \): The length \( r \) is half the length of one side of the base of the pyramid, which can be found using the relationship among the sides in the right triangle formed by the height \( h \), the length \( r \), and the slant height \( s \).

    For a square pyramid, we have: \[ e^2 = h^2 + r^2 \] and \[ s^2 = h^2 + r^2 \]

    From the given values: \[ 25^2 = h^2 + r^2 \] which simplifies to: \[ 625 = h^2 + r^2 \quad \text{(1)} \]

    Also, from the slant height: \[ 24^2 = h^2 + r^2 \] which simplifies to: \[ 576 = h^2 + r^2 \quad \text{(2)} \]

    Since \( s^2 \) must equal \( r^2 \), we now have two equations, which should yield the same expressions for \( h \).

  3. Equate the equations: From (1) and (2): \[ h^2 + r^2 = 625 \] \[ h^2 + r^2 = 576 \]

    We must now analyze the steps with the correct relationships.

  4. Use the right triangle: Within the triangle formed by \( h \), \( r \) (where \( r \) is half of the base edge, which we can find by considering \( s \)).

Relating \( s \) and \( r \): \[ s^2 = r^2 + h^2 \rightarrow 24^2 = r^2 + h^2 \] Thus, setting up with \( h \) in terms of \( s \): \[ h^2 = s^2 - r^2 \quad \ldots \tag{3} \]

Next we can state \[ 24^2 = h^2 + r^2 \Rightarrow r^2 = 24^2 - h^2 = 576 - h^2 \]

  1. Substituting back into the lateral edge equation: To solve for \( h \): \[ 625 = h^2 + (576 - h^2) \] We get: \[ 625 = 576 + r^2 \rightarrow r^2 = 625 - 576 = 49 \] Then: \[ r = 7 \]

  2. Finding \( h \): Now, substitute back for height \( h \) using \( r^2 + h^2 = 576\): \[ h^2 = 576 - 49 \rightarrow h^2 = 527 \] Finally, solving for \( h \): \[ h = \sqrt{527} \approx 22.9 \]

Rounding to the nearest whole number gives:

The height of the square pyramid is \( 23 \) inches.