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Finding the Fourth Proportional to 720.72, 1,081.26 and 287.89

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Solution

The fourth proportional to 720.72, 1,081.26 and 287.89 is: 431.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.72 : 1,081.26 = 287.89 : x
  2. Step 2: Convert to fraction form
    720.72/1,081.26 = 287.89/x
  3. Step 3: Cross multiply
    720.72x = 1,081.26 × 287.89
  4. Step 4: Simplify right side
    720.72x = 311,281.24
  5. Step 5: Solve for x
    x = 311,281.24/720.72
  6. Step 6: Final answer
    x = 431.90

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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.