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Finding the Fourth Proportional to 771.65, 1,157.20 and 478.70

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Solution

The fourth proportional to 771.65, 1,157.20 and 478.70 is: 717.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.65 : 1,157.20 = 478.70 : x
  2. Step 2: Convert to fraction form
    771.65/1,157.20 = 478.70/x
  3. Step 3: Cross multiply
    771.65x = 1,157.20 × 478.70
  4. Step 4: Simplify right side
    771.65x = 553,951.64
  5. Step 5: Solve for x
    x = 553,951.64/771.65
  6. Step 6: Final answer
    x = 717.88

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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.