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Finding the Fourth Proportional to 620.56, 856.20 and 355

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Solution

The fourth proportional to 620.56, 856.20 and 355 is: 489.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.56 : 856.20 = 355 : x
  2. Step 2: Convert to fraction form
    620.56/856.20 = 355/x
  3. Step 3: Cross multiply
    620.56x = 856.20 × 355
  4. Step 4: Simplify right side
    620.56x = 303,951
  5. Step 5: Solve for x
    x = 303,951/620.56
  6. Step 6: Final answer
    x = 489.80

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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.