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Finding the Fourth Proportional to 390.08, 585.12 and 261.92

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Solution

The fourth proportional to 390.08, 585.12 and 261.92 is: 392.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.08 : 585.12 = 261.92 : x
  2. Step 2: Convert to fraction form
    390.08/585.12 = 261.92/x
  3. Step 3: Cross multiply
    390.08x = 585.12 × 261.92
  4. Step 4: Simplify right side
    390.08x = 153,254.63
  5. Step 5: Solve for x
    x = 153,254.63/390.08
  6. Step 6: Final answer
    x = 392.88

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.