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Finding the Fourth Proportional to 720.43, 1,079.57 and 431.55

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Solution

The fourth proportional to 720.43, 1,079.57 and 431.55 is: 646.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.43 : 1,079.57 = 431.55 : x
  2. Step 2: Convert to fraction form
    720.43/1,079.57 = 431.55/x
  3. Step 3: Cross multiply
    720.43x = 1,079.57 × 431.55
  4. Step 4: Simplify right side
    720.43x = 465,886.28
  5. Step 5: Solve for x
    x = 465,886.28/720.43
  6. Step 6: Final answer
    x = 646.68

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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.