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Finding the Fourth Proportional to 390.34, 585.80 and 287.90

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Solution

The fourth proportional to 390.34, 585.80 and 287.90 is: 432.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.34 : 585.80 = 287.90 : x
  2. Step 2: Convert to fraction form
    390.34/585.80 = 287.90/x
  3. Step 3: Cross multiply
    390.34x = 585.80 × 287.90
  4. Step 4: Simplify right side
    390.34x = 168,651.82
  5. Step 5: Solve for x
    x = 168,651.82/390.34
  6. Step 6: Final answer
    x = 432.06

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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.