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Finding the Fourth Proportional to 1,280.55, 1,920.15 and 458.70

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Solution

The fourth proportional to 1,280.55, 1,920.15 and 458.70 is: 687.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.55 : 1,920.15 = 458.70 : x
  2. Step 2: Convert to fraction form
    1,280.55/1,920.15 = 458.70/x
  3. Step 3: Cross multiply
    1,280.55x = 1,920.15 × 458.70
  4. Step 4: Simplify right side
    1,280.55x = 880,772.81
  5. Step 5: Solve for x
    x = 880,772.81/1,280.55
  6. Step 6: Final answer
    x = 687.81

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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.