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Finding the Fourth Proportional to 689.81, 1,035.05 and 429.72

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Solution

The fourth proportional to 689.81, 1,035.05 and 429.72 is: 644.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.81 : 1,035.05 = 429.72 : x
  2. Step 2: Convert to fraction form
    689.81/1,035.05 = 429.72/x
  3. Step 3: Cross multiply
    689.81x = 1,035.05 × 429.72
  4. Step 4: Simplify right side
    689.81x = 444,779.54
  5. Step 5: Solve for x
    x = 444,779.54/689.81
  6. Step 6: Final answer
    x = 644.79

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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.