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Finding the Fourth Proportional to 881.64, 1,216.92 and 645.72

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Solution

The fourth proportional to 881.64, 1,216.92 and 645.72 is: 891.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    881.64 : 1,216.92 = 645.72 : x
  2. Step 2: Convert to fraction form
    881.64/1,216.92 = 645.72/x
  3. Step 3: Cross multiply
    881.64x = 1,216.92 × 645.72
  4. Step 4: Simplify right side
    881.64x = 785,789.58
  5. Step 5: Solve for x
    x = 785,789.58/881.64
  6. Step 6: Final answer
    x = 891.28

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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.