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Finding the Fourth Proportional to 978.12, 1,350.23 and 645.96

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Solution

The fourth proportional to 978.12, 1,350.23 and 645.96 is: 891.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.12 : 1,350.23 = 645.96 : x
  2. Step 2: Convert to fraction form
    978.12/1,350.23 = 645.96/x
  3. Step 3: Cross multiply
    978.12x = 1,350.23 × 645.96
  4. Step 4: Simplify right side
    978.12x = 872,191.34
  5. Step 5: Solve for x
    x = 872,191.34/978.12
  6. Step 6: Final answer
    x = 891.70

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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.