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Finding the Fourth Proportional to 771.46, 1,064.74 and 491.81

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Solution

The fourth proportional to 771.46, 1,064.74 and 491.81 is: 678.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.46 : 1,064.74 = 491.81 : x
  2. Step 2: Convert to fraction form
    771.46/1,064.74 = 491.81/x
  3. Step 3: Cross multiply
    771.46x = 1,064.74 × 491.81
  4. Step 4: Simplify right side
    771.46x = 523,649.78
  5. Step 5: Solve for x
    x = 523,649.78/771.46
  6. Step 6: Final answer
    x = 678.78

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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.