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Finding the Fourth Proportional to 978.02, 1,349.78 and 623.96

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Solution

The fourth proportional to 978.02, 1,349.78 and 623.96 is: 861.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.02 : 1,349.78 = 623.96 : x
  2. Step 2: Convert to fraction form
    978.02/1,349.78 = 623.96/x
  3. Step 3: Cross multiply
    978.02x = 1,349.78 × 623.96
  4. Step 4: Simplify right side
    978.02x = 842,198.86
  5. Step 5: Solve for x
    x = 842,198.86/978.02
  6. Step 6: Final answer
    x = 861.12

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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.