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Finding the Fourth Proportional to 647.76, 893.74 and 399.20

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Solution

The fourth proportional to 647.76, 893.74 and 399.20 is: 550.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.76 : 893.74 = 399.20 : x
  2. Step 2: Convert to fraction form
    647.76/893.74 = 399.20/x
  3. Step 3: Cross multiply
    647.76x = 893.74 × 399.20
  4. Step 4: Simplify right side
    647.76x = 356,781.01
  5. Step 5: Solve for x
    x = 356,781.01/647.76
  6. Step 6: Final answer
    x = 550.79

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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.