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Finding the Fourth Proportional to 561.28, 774.56 and 312.61

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Solution

The fourth proportional to 561.28, 774.56 and 312.61 is: 431.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    561.28 : 774.56 = 312.61 : x
  2. Step 2: Convert to fraction form
    561.28/774.56 = 312.61/x
  3. Step 3: Cross multiply
    561.28x = 774.56 × 312.61
  4. Step 4: Simplify right side
    561.28x = 242,135.20
  5. Step 5: Solve for x
    x = 242,135.20/561.28
  6. Step 6: Final answer
    x = 431.40

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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.