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Finding the Fourth Proportional to 620.67, 856.67 and 387.75

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Solution

The fourth proportional to 620.67, 856.67 and 387.75 is: 535.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.67 : 856.67 = 387.75 : x
  2. Step 2: Convert to fraction form
    620.67/856.67 = 387.75/x
  3. Step 3: Cross multiply
    620.67x = 856.67 × 387.75
  4. Step 4: Simplify right side
    620.67x = 332,171.85
  5. Step 5: Solve for x
    x = 332,171.85/620.67
  6. Step 6: Final answer
    x = 535.18

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.