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Finding the Fourth Proportional to 621.42, 856.98 and 400.20

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Solution

The fourth proportional to 621.42, 856.98 and 400.20 is: 551.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.42 : 856.98 = 400.20 : x
  2. Step 2: Convert to fraction form
    621.42/856.98 = 400.20/x
  3. Step 3: Cross multiply
    621.42x = 856.98 × 400.20
  4. Step 4: Simplify right side
    621.42x = 342,963.40
  5. Step 5: Solve for x
    x = 342,963.40/621.42
  6. Step 6: Final answer
    x = 551.90

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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.