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Finding the Fourth Proportional to 390.58, 539.48 and 387.88

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Solution

The fourth proportional to 390.58, 539.48 and 387.88 is: 535.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.58 : 539.48 = 387.88 : x
  2. Step 2: Convert to fraction form
    390.58/539.48 = 387.88/x
  3. Step 3: Cross multiply
    390.58x = 539.48 × 387.88
  4. Step 4: Simplify right side
    390.58x = 209,253.50
  5. Step 5: Solve for x
    x = 209,253.50/390.58
  6. Step 6: Final answer
    x = 535.75

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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.