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Finding the Fourth Proportional to 439.02, 655.70 and 390.42

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Solution

The fourth proportional to 439.02, 655.70 and 390.42 is: 583.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.02 : 655.70 = 390.42 : x
  2. Step 2: Convert to fraction form
    439.02/655.70 = 390.42/x
  3. Step 3: Cross multiply
    439.02x = 655.70 × 390.42
  4. Step 4: Simplify right side
    439.02x = 255,996.44
  5. Step 5: Solve for x
    x = 255,996.44/439.02
  6. Step 6: Final answer
    x = 583.11

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.