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Finding the Fourth Proportional to 679.50, 1,018.58 and 405.72

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Solution

The fourth proportional to 679.50, 1,018.58 and 405.72 is: 608.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.50 : 1,018.58 = 405.72 : x
  2. Step 2: Convert to fraction form
    679.50/1,018.58 = 405.72/x
  3. Step 3: Cross multiply
    679.50x = 1,018.58 × 405.72
  4. Step 4: Simplify right side
    679.50x = 413,258.28
  5. Step 5: Solve for x
    x = 413,258.28/679.50
  6. Step 6: Final answer
    x = 608.18

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.