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Finding the Fourth Proportional to 978.40, 1,350.60 and 664.24

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Solution

The fourth proportional to 978.40, 1,350.60 and 664.24 is: 916.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.40 : 1,350.60 = 664.24 : x
  2. Step 2: Convert to fraction form
    978.40/1,350.60 = 664.24/x
  3. Step 3: Cross multiply
    978.40x = 1,350.60 × 664.24
  4. Step 4: Simplify right side
    978.40x = 897,122.54
  5. Step 5: Solve for x
    x = 897,122.54/978.40
  6. Step 6: Final answer
    x = 916.93

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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.