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Finding the Fourth Proportional to 438.98, 655.35 and 390.38

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Solution

The fourth proportional to 438.98, 655.35 and 390.38 is: 582.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.98 : 655.35 = 390.38 : x
  2. Step 2: Convert to fraction form
    438.98/655.35 = 390.38/x
  3. Step 3: Cross multiply
    438.98x = 655.35 × 390.38
  4. Step 4: Simplify right side
    438.98x = 255,830.79
  5. Step 5: Solve for x
    x = 255,830.79/438.98
  6. Step 6: Final answer
    x = 582.79

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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.