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Finding the Fourth Proportional to 390.36, 538.32 and 257.44

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Solution

The fourth proportional to 390.36, 538.32 and 257.44 is: 355.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.36 : 538.32 = 257.44 : x
  2. Step 2: Convert to fraction form
    390.36/538.32 = 257.44/x
  3. Step 3: Cross multiply
    390.36x = 538.32 × 257.44
  4. Step 4: Simplify right side
    390.36x = 138,585.10
  5. Step 5: Solve for x
    x = 138,585.10/390.36
  6. Step 6: Final answer
    x = 355.02

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.