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Finding the Fourth Proportional to 439.34, 655.76 and 387.45

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Solution

The fourth proportional to 439.34, 655.76 and 387.45 is: 578.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.34 : 655.76 = 387.45 : x
  2. Step 2: Convert to fraction form
    439.34/655.76 = 387.45/x
  3. Step 3: Cross multiply
    439.34x = 655.76 × 387.45
  4. Step 4: Simplify right side
    439.34x = 254,074.93
  5. Step 5: Solve for x
    x = 254,074.93/439.34
  6. Step 6: Final answer
    x = 578.32

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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.