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Finding the Fourth Proportional to 620.76, 856.50 and 387.72

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Solution

The fourth proportional to 620.76, 856.50 and 387.72 is: 534.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.76 : 856.50 = 387.72 : x
  2. Step 2: Convert to fraction form
    620.76/856.50 = 387.72/x
  3. Step 3: Cross multiply
    620.76x = 856.50 × 387.72
  4. Step 4: Simplify right side
    620.76x = 332,082.18
  5. Step 5: Solve for x
    x = 332,082.18/620.76
  6. Step 6: Final answer
    x = 534.96

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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.