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Finding the Fourth Proportional to 1,355.40, 2,029.90 and 920.20

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Solution

The fourth proportional to 1,355.40, 2,029.90 and 920.20 is: 1,378.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,355.40 : 2,029.90 = 920.20 : x
  2. Step 2: Convert to fraction form
    1,355.40/2,029.90 = 920.20/x
  3. Step 3: Cross multiply
    1,355.40x = 2,029.90 × 920.20
  4. Step 4: Simplify right side
    1,355.40x = 1,867,913.98
  5. Step 5: Solve for x
    x = 1,867,913.98/1,355.40
  6. Step 6: Final answer
    x = 1,378.13

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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.