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Finding the Fourth Proportional to 386.85, 580.31 and 140.21

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Solution

The fourth proportional to 386.85, 580.31 and 140.21 is: 210.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.85 : 580.31 = 140.21 : x
  2. Step 2: Convert to fraction form
    386.85/580.31 = 140.21/x
  3. Step 3: Cross multiply
    386.85x = 580.31 × 140.21
  4. Step 4: Simplify right side
    386.85x = 81,362.19
  5. Step 5: Solve for x
    x = 81,362.19/386.85
  6. Step 6: Final answer
    x = 210.32

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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.