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Finding the Fourth Proportional to 659.85, 989.42 and 505.39

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Solution

The fourth proportional to 659.85, 989.42 and 505.39 is: 757.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.85 : 989.42 = 505.39 : x
  2. Step 2: Convert to fraction form
    659.85/989.42 = 505.39/x
  3. Step 3: Cross multiply
    659.85x = 989.42 × 505.39
  4. Step 4: Simplify right side
    659.85x = 500,039.83
  5. Step 5: Solve for x
    x = 500,039.83/659.85
  6. Step 6: Final answer
    x = 757.81

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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.