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Finding the Fourth Proportional to 720.28, 1,079.81 and 309.31

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Solution

The fourth proportional to 720.28, 1,079.81 and 309.31 is: 463.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.28 : 1,079.81 = 309.31 : x
  2. Step 2: Convert to fraction form
    720.28/1,079.81 = 309.31/x
  3. Step 3: Cross multiply
    720.28x = 1,079.81 × 309.31
  4. Step 4: Simplify right side
    720.28x = 333,996.03
  5. Step 5: Solve for x
    x = 333,996.03/720.28
  6. Step 6: Final answer
    x = 463.70

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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.