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Finding the Fourth Proportional to 878.50, 1,211.56 and 631.45

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Solution

The fourth proportional to 878.50, 1,211.56 and 631.45 is: 870.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.50 : 1,211.56 = 631.45 : x
  2. Step 2: Convert to fraction form
    878.50/1,211.56 = 631.45/x
  3. Step 3: Cross multiply
    878.50x = 1,211.56 × 631.45
  4. Step 4: Simplify right side
    878.50x = 765,032.68
  5. Step 5: Solve for x
    x = 765,032.68/878.50
  6. Step 6: Final answer
    x = 870.84

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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.