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Finding the Fourth Proportional to 438.21, 654.35 and 391.64

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Solution

The fourth proportional to 438.21, 654.35 and 391.64 is: 584.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.21 : 654.35 = 391.64 : x
  2. Step 2: Convert to fraction form
    438.21/654.35 = 391.64/x
  3. Step 3: Cross multiply
    438.21x = 654.35 × 391.64
  4. Step 4: Simplify right side
    438.21x = 256,264.40
  5. Step 5: Solve for x
    x = 256,264.40/438.21
  6. Step 6: Final answer
    x = 584.80

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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.