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Finding the Fourth Proportional to 386.18, 578.90 and 129.50

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Solution

The fourth proportional to 386.18, 578.90 and 129.50 is: 194.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.18 : 578.90 = 129.50 : x
  2. Step 2: Convert to fraction form
    386.18/578.90 = 129.50/x
  3. Step 3: Cross multiply
    386.18x = 578.90 × 129.50
  4. Step 4: Simplify right side
    386.18x = 74,967.55
  5. Step 5: Solve for x
    x = 74,967.55/386.18
  6. Step 6: Final answer
    x = 194.13

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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.