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Finding the Fourth Proportional to 870.62, 1,305.11 and 431.60

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Solution

The fourth proportional to 870.62, 1,305.11 and 431.60 is: 646.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.62 : 1,305.11 = 431.60 : x
  2. Step 2: Convert to fraction form
    870.62/1,305.11 = 431.60/x
  3. Step 3: Cross multiply
    870.62x = 1,305.11 × 431.60
  4. Step 4: Simplify right side
    870.62x = 563,280.03
  5. Step 5: Solve for x
    x = 563,280.03/870.62
  6. Step 6: Final answer
    x = 646.99

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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.