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Finding the Fourth Proportional to 386.90, 580.29 and 143.39

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Solution

The fourth proportional to 386.90, 580.29 and 143.39 is: 215.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.90 : 580.29 = 143.39 : x
  2. Step 2: Convert to fraction form
    386.90/580.29 = 143.39/x
  3. Step 3: Cross multiply
    386.90x = 580.29 × 143.39
  4. Step 4: Simplify right side
    386.90x = 83,209.77
  5. Step 5: Solve for x
    x = 83,209.77/386.90
  6. Step 6: Final answer
    x = 215.07

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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.