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Finding the Fourth Proportional to 492.40, 679.35 and 305.79

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Solution

The fourth proportional to 492.40, 679.35 and 305.79 is: 421.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    492.40 : 679.35 = 305.79 : x
  2. Step 2: Convert to fraction form
    492.40/679.35 = 305.79/x
  3. Step 3: Cross multiply
    492.40x = 679.35 × 305.79
  4. Step 4: Simplify right side
    492.40x = 207,738.44
  5. Step 5: Solve for x
    x = 207,738.44/492.40
  6. Step 6: Final answer
    x = 421.89

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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.