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Finding the Fourth Proportional to 390, 585.09 and 133.50

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Solution

The fourth proportional to 390, 585.09 and 133.50 is: 200.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    390 : 585.09 = 133.50 : x
  2. Step 2: Convert to fraction form
    390/585.09 = 133.50/x
  3. Step 3: Cross multiply
    390x = 585.09 × 133.50
  4. Step 4: Simplify right side
    390x = 78,109.52
  5. Step 5: Solve for x
    x = 78,109.52/390
  6. Step 6: Final answer
    x = 200.28

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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.