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Finding the Fourth Proportional to 671.12, 920.63 and 642.77

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Solution

The fourth proportional to 671.12, 920.63 and 642.77 is: 881.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    671.12 : 920.63 = 642.77 : x
  2. Step 2: Convert to fraction form
    671.12/920.63 = 642.77/x
  3. Step 3: Cross multiply
    671.12x = 920.63 × 642.77
  4. Step 4: Simplify right side
    671.12x = 591,753.80
  5. Step 5: Solve for x
    x = 591,753.80/671.12
  6. Step 6: Final answer
    x = 881.74

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.