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Finding the Fourth Proportional to 871.60, 1,305.78 and 742

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Solution

The fourth proportional to 871.60, 1,305.78 and 742 is: 1,111.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.60 : 1,305.78 = 742 : x
  2. Step 2: Convert to fraction form
    871.60/1,305.78 = 742/x
  3. Step 3: Cross multiply
    871.60x = 1,305.78 × 742
  4. Step 4: Simplify right side
    871.60x = 968,888.76
  5. Step 5: Solve for x
    x = 968,888.76/871.60
  6. Step 6: Final answer
    x = 1,111.62

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.