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Finding the Fourth Proportional to 1,122.31, 1,683.36 and 428.68

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Solution

The fourth proportional to 1,122.31, 1,683.36 and 428.68 is: 642.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,122.31 : 1,683.36 = 428.68 : x
  2. Step 2: Convert to fraction form
    1,122.31/1,683.36 = 428.68/x
  3. Step 3: Cross multiply
    1,122.31x = 1,683.36 × 428.68
  4. Step 4: Simplify right side
    1,122.31x = 721,622.76
  5. Step 5: Solve for x
    x = 721,622.76/1,122.31
  6. Step 6: Final answer
    x = 642.98

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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.