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Finding the Fourth Proportional to 305.98, 421.72 and 289.56

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Solution

The fourth proportional to 305.98, 421.72 and 289.56 is: 399.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.98 : 421.72 = 289.56 : x
  2. Step 2: Convert to fraction form
    305.98/421.72 = 289.56/x
  3. Step 3: Cross multiply
    305.98x = 421.72 × 289.56
  4. Step 4: Simplify right side
    305.98x = 122,113.24
  5. Step 5: Solve for x
    x = 122,113.24/305.98
  6. Step 6: Final answer
    x = 399.09

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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.