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Finding the Fourth Proportional to 609.84, 915.48 and 428.40

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Solution

The fourth proportional to 609.84, 915.48 and 428.40 is: 643.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    609.84 : 915.48 = 428.40 : x
  2. Step 2: Convert to fraction form
    609.84/915.48 = 428.40/x
  3. Step 3: Cross multiply
    609.84x = 915.48 × 428.40
  4. Step 4: Simplify right side
    609.84x = 392,191.63
  5. Step 5: Solve for x
    x = 392,191.63/609.84
  6. Step 6: Final answer
    x = 643.11

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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.