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Finding the Fourth Proportional to 386.80, 580.28 and 143.40

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Solution

The fourth proportional to 386.80, 580.28 and 143.40 is: 215.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.80 : 580.28 = 143.40 : x
  2. Step 2: Convert to fraction form
    386.80/580.28 = 143.40/x
  3. Step 3: Cross multiply
    386.80x = 580.28 × 143.40
  4. Step 4: Simplify right side
    386.80x = 83,212.15
  5. Step 5: Solve for x
    x = 83,212.15/386.80
  6. Step 6: Final answer
    x = 215.13

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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.