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Finding the Fourth Proportional to 382.78, 528.40 and 258.40

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Solution

The fourth proportional to 382.78, 528.40 and 258.40 is: 356.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    382.78 : 528.40 = 258.40 : x
  2. Step 2: Convert to fraction form
    382.78/528.40 = 258.40/x
  3. Step 3: Cross multiply
    382.78x = 528.40 × 258.40
  4. Step 4: Simplify right side
    382.78x = 136,538.56
  5. Step 5: Solve for x
    x = 136,538.56/382.78
  6. Step 6: Final answer
    x = 356.70

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.