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Finding the Fourth Proportional to 771.72, 1,155.51 and 405.74

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Solution

The fourth proportional to 771.72, 1,155.51 and 405.74 is: 607.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.72 : 1,155.51 = 405.74 : x
  2. Step 2: Convert to fraction form
    771.72/1,155.51 = 405.74/x
  3. Step 3: Cross multiply
    771.72x = 1,155.51 × 405.74
  4. Step 4: Simplify right side
    771.72x = 468,830.85
  5. Step 5: Solve for x
    x = 468,830.85/771.72
  6. Step 6: Final answer
    x = 607.51

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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.