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Finding the Fourth Proportional to 768.21, 1,152.38 and 378.91

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Solution

The fourth proportional to 768.21, 1,152.38 and 378.91 is: 568.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    768.21 : 1,152.38 = 378.91 : x
  2. Step 2: Convert to fraction form
    768.21/1,152.38 = 378.91/x
  3. Step 3: Cross multiply
    768.21x = 1,152.38 × 378.91
  4. Step 4: Simplify right side
    768.21x = 436,648.31
  5. Step 5: Solve for x
    x = 436,648.31/768.21
  6. Step 6: Final answer
    x = 568.40

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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.