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Finding the Fourth Proportional to 621.13, 856.95 and 388.39

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Solution

The fourth proportional to 621.13, 856.95 and 388.39 is: 535.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.13 : 856.95 = 388.39 : x
  2. Step 2: Convert to fraction form
    621.13/856.95 = 388.39/x
  3. Step 3: Cross multiply
    621.13x = 856.95 × 388.39
  4. Step 4: Simplify right side
    621.13x = 332,830.81
  5. Step 5: Solve for x
    x = 332,830.81/621.13
  6. Step 6: Final answer
    x = 535.85

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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.