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Finding the Fourth Proportional to 771.65, 1,065.05 and 491.82

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Solution

The fourth proportional to 771.65, 1,065.05 and 491.82 is: 678.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.65 : 1,065.05 = 491.82 : x
  2. Step 2: Convert to fraction form
    771.65/1,065.05 = 491.82/x
  3. Step 3: Cross multiply
    771.65x = 1,065.05 × 491.82
  4. Step 4: Simplify right side
    771.65x = 523,814.27
  5. Step 5: Solve for x
    x = 523,814.27/771.65
  6. Step 6: Final answer
    x = 678.82

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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.