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Finding the Fourth Proportional to 720.70, 1,081.08 and 431.50

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Solution

The fourth proportional to 720.70, 1,081.08 and 431.50 is: 647.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.70 : 1,081.08 = 431.50 : x
  2. Step 2: Convert to fraction form
    720.70/1,081.08 = 431.50/x
  3. Step 3: Cross multiply
    720.70x = 1,081.08 × 431.50
  4. Step 4: Simplify right side
    720.70x = 466,486.02
  5. Step 5: Solve for x
    x = 466,486.02/720.70
  6. Step 6: Final answer
    x = 647.27

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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.