Find the Face Diagonal of a Rectangular Prism with Base Diagonal X and Length 3X

Question

A rectangular prism has a square base with a diagonal length of X.

The prism has a length of 3X.

How long is the diagonal of the rectangular face of the prism.

3X3X3XXXXAAABBBCCCDDDAAA111BBB111CCC111DDD111

Video Solution

Solution Steps

00:00 Calculate the diagonal length of the rectangular faces in the box
00:03 Box is square according to the given data, therefore sides are equal
00:07 In a square all angles are right angles
00:12 We'll use the Pythagorean theorem in triangle A1D1C1 to find A1C1
00:15 We'll substitute appropriate values according to the given data and solve to find X
00:22 This is the length of diagonal face X
00:28 We'll express Y using X
00:38 Each face in the box is a rectangle, therefore all angles are right angles
00:47 We'll use the Pythagorean theorem in triangle AA1D1 to find AD1
00:58 We'll substitute appropriate values according to the given data and solve to find AD1
01:18 Group terms
01:22 Take the square root
01:26 This is the length of the diagonal of the rectangular faces in the box
01:29 And this is the solution to the problem

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Determine the side length of the square base
  • Step 2: Calculate the diagonal of the rectangular face using the Pythagorean theorem

Now, let's work through each step:
Step 1: The side length s s of the square base is calculated from its diagonal X X as s=X2 s = \frac{X}{\sqrt{2}} .
Step 2: The diagonal d d of the rectangular face is found using d2=s2+(3X)2 d^2 = s^2 + (3X)^2 , which simplifies to d=X9.5 d = X\sqrt{9.5} .

The solution to the problem is x9.5 x\sqrt{9.5} .

Answer

x9.5 x\sqrt{9.5}