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Finding the Fourth Proportional to 720.42, 1,080.09 and 309.21

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Solution

The fourth proportional to 720.42, 1,080.09 and 309.21 is: 463.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.42 : 1,080.09 = 309.21 : x
  2. Step 2: Convert to fraction form
    720.42/1,080.09 = 309.21/x
  3. Step 3: Cross multiply
    720.42x = 1,080.09 × 309.21
  4. Step 4: Simplify right side
    720.42x = 333,974.63
  5. Step 5: Solve for x
    x = 333,974.63/720.42
  6. Step 6: Final answer
    x = 463.58

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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.