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Finding the Fourth Proportional to 878.61, 1,212.51 and 485.66

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Solution

The fourth proportional to 878.61, 1,212.51 and 485.66 is: 670.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.61 : 1,212.51 = 485.66 : x
  2. Step 2: Convert to fraction form
    878.61/1,212.51 = 485.66/x
  3. Step 3: Cross multiply
    878.61x = 1,212.51 × 485.66
  4. Step 4: Simplify right side
    878.61x = 588,864.27
  5. Step 5: Solve for x
    x = 588,864.27/878.61
  6. Step 6: Final answer
    x = 670.22

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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.