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Finding the Fourth Proportional to 621.11, 856.77 and 455.12

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Solution

The fourth proportional to 621.11, 856.77 and 455.12 is: 627.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.11 : 856.77 = 455.12 : x
  2. Step 2: Convert to fraction form
    621.11/856.77 = 455.12/x
  3. Step 3: Cross multiply
    621.11x = 856.77 × 455.12
  4. Step 4: Simplify right side
    621.11x = 389,933.16
  5. Step 5: Solve for x
    x = 389,933.16/621.11
  6. Step 6: Final answer
    x = 627.80

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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.