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Finding the Fourth Proportional to 878.72, 1,212.80 and 657.28

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Solution

The fourth proportional to 878.72, 1,212.80 and 657.28 is: 907.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.72 : 1,212.80 = 657.28 : x
  2. Step 2: Convert to fraction form
    878.72/1,212.80 = 657.28/x
  3. Step 3: Cross multiply
    878.72x = 1,212.80 × 657.28
  4. Step 4: Simplify right side
    878.72x = 797,149.18
  5. Step 5: Solve for x
    x = 797,149.18/878.72
  6. Step 6: Final answer
    x = 907.17

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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.