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Finding the Fourth Proportional to 647.98, 893.91 and 399.21

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Solution

The fourth proportional to 647.98, 893.91 and 399.21 is: 550.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.98 : 893.91 = 399.21 : x
  2. Step 2: Convert to fraction form
    647.98/893.91 = 399.21/x
  3. Step 3: Cross multiply
    647.98x = 893.91 × 399.21
  4. Step 4: Simplify right side
    647.98x = 356,857.81
  5. Step 5: Solve for x
    x = 356,857.81/647.98
  6. Step 6: Final answer
    x = 550.72

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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.