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Finding the Fourth Proportional to 978.48, 1,351.62 and 813.24

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Solution

The fourth proportional to 978.48, 1,351.62 and 813.24 is: 1,123.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.48 : 1,351.62 = 813.24 : x
  2. Step 2: Convert to fraction form
    978.48/1,351.62 = 813.24/x
  3. Step 3: Cross multiply
    978.48x = 1,351.62 × 813.24
  4. Step 4: Simplify right side
    978.48x = 1,099,191.45
  5. Step 5: Solve for x
    x = 1,099,191.45/978.48
  6. Step 6: Final answer
    x = 1,123.37

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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.