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Finding the Fourth Proportional to 771.10, 1,064.47 and 491.72

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Solution

The fourth proportional to 771.10, 1,064.47 and 491.72 is: 678.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.10 : 1,064.47 = 491.72 : x
  2. Step 2: Convert to fraction form
    771.10/1,064.47 = 491.72/x
  3. Step 3: Cross multiply
    771.10x = 1,064.47 × 491.72
  4. Step 4: Simplify right side
    771.10x = 523,420.47
  5. Step 5: Solve for x
    x = 523,420.47/771.10
  6. Step 6: Final answer
    x = 678.80

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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.