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Finding the Fourth Proportional to 1,280.63, 1,920.85 and 458.86

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Solution

The fourth proportional to 1,280.63, 1,920.85 and 458.86 is: 688.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.63 : 1,920.85 = 458.86 : x
  2. Step 2: Convert to fraction form
    1,280.63/1,920.85 = 458.86/x
  3. Step 3: Cross multiply
    1,280.63x = 1,920.85 × 458.86
  4. Step 4: Simplify right side
    1,280.63x = 881,401.23
  5. Step 5: Solve for x
    x = 881,401.23/1,280.63
  6. Step 6: Final answer
    x = 688.26

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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.