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Finding the Fourth Proportional to 621.78, 858 and 345.78

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Solution

The fourth proportional to 621.78, 858 and 345.78 is: 477.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.78 : 858 = 345.78 : x
  2. Step 2: Convert to fraction form
    621.78/858 = 345.78/x
  3. Step 3: Cross multiply
    621.78x = 858 × 345.78
  4. Step 4: Simplify right side
    621.78x = 296,679.24
  5. Step 5: Solve for x
    x = 296,679.24/621.78
  6. Step 6: Final answer
    x = 477.15

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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.