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Finding the Fourth Proportional to 256.80, 384.90 and 126.72

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Solution

The fourth proportional to 256.80, 384.90 and 126.72 is: 189.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.80 : 384.90 = 126.72 : x
  2. Step 2: Convert to fraction form
    256.80/384.90 = 126.72/x
  3. Step 3: Cross multiply
    256.80x = 384.90 × 126.72
  4. Step 4: Simplify right side
    256.80x = 48,774.53
  5. Step 5: Solve for x
    x = 48,774.53/256.80
  6. Step 6: Final answer
    x = 189.93

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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.