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Finding the Fourth Proportional to 878.89, 1,212.84 and 485.91

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Solution

The fourth proportional to 878.89, 1,212.84 and 485.91 is: 670.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.89 : 1,212.84 = 485.91 : x
  2. Step 2: Convert to fraction form
    878.89/1,212.84 = 485.91/x
  3. Step 3: Cross multiply
    878.89x = 1,212.84 × 485.91
  4. Step 4: Simplify right side
    878.89x = 589,331.08
  5. Step 5: Solve for x
    x = 589,331.08/878.89
  6. Step 6: Final answer
    x = 670.54

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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.