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Finding the Fourth Proportional to 720.64, 1,081.05 and 287.70

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Solution

The fourth proportional to 720.64, 1,081.05 and 287.70 is: 431.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.64 : 1,081.05 = 287.70 : x
  2. Step 2: Convert to fraction form
    720.64/1,081.05 = 287.70/x
  3. Step 3: Cross multiply
    720.64x = 1,081.05 × 287.70
  4. Step 4: Simplify right side
    720.64x = 311,018.09
  5. Step 5: Solve for x
    x = 311,018.09/720.64
  6. Step 6: Final answer
    x = 431.59

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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.