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Finding the Fourth Proportional to 620.12, 855.07 and 398.76

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Solution

The fourth proportional to 620.12, 855.07 and 398.76 is: 549.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.12 : 855.07 = 398.76 : x
  2. Step 2: Convert to fraction form
    620.12/855.07 = 398.76/x
  3. Step 3: Cross multiply
    620.12x = 855.07 × 398.76
  4. Step 4: Simplify right side
    620.12x = 340,966.72
  5. Step 5: Solve for x
    x = 340,966.72/620.12
  6. Step 6: Final answer
    x = 549.84

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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.