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Finding the Fourth Proportional to 491.37, 678.96 and 393.90

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Solution

The fourth proportional to 491.37, 678.96 and 393.90 is: 544.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.37 : 678.96 = 393.90 : x
  2. Step 2: Convert to fraction form
    491.37/678.96 = 393.90/x
  3. Step 3: Cross multiply
    491.37x = 678.96 × 393.90
  4. Step 4: Simplify right side
    491.37x = 267,442.34
  5. Step 5: Solve for x
    x = 267,442.34/491.37
  6. Step 6: Final answer
    x = 544.28

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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.