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Finding the Fourth Proportional to 720.18, 1,079.19 and 431.30

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Solution

The fourth proportional to 720.18, 1,079.19 and 431.30 is: 646.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.18 : 1,079.19 = 431.30 : x
  2. Step 2: Convert to fraction form
    720.18/1,079.19 = 431.30/x
  3. Step 3: Cross multiply
    720.18x = 1,079.19 × 431.30
  4. Step 4: Simplify right side
    720.18x = 465,454.65
  5. Step 5: Solve for x
    x = 465,454.65/720.18
  6. Step 6: Final answer
    x = 646.30

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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.