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Finding the Fourth Proportional to 390.30, 585.45 and 97.80

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Solution

The fourth proportional to 390.30, 585.45 and 97.80 is: 146.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.30 : 585.45 = 97.80 : x
  2. Step 2: Convert to fraction form
    390.30/585.45 = 97.80/x
  3. Step 3: Cross multiply
    390.30x = 585.45 × 97.80
  4. Step 4: Simplify right side
    390.30x = 57,253.59
  5. Step 5: Solve for x
    x = 57,253.59/390.30
  6. Step 6: Final answer
    x = 146.69

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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.