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Finding the Fourth Proportional to 881.40, 1,215.85 and 561.78

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Solution

The fourth proportional to 881.40, 1,215.85 and 561.78 is: 774.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    881.40 : 1,215.85 = 561.78 : x
  2. Step 2: Convert to fraction form
    881.40/1,215.85 = 561.78/x
  3. Step 3: Cross multiply
    881.40x = 1,215.85 × 561.78
  4. Step 4: Simplify right side
    881.40x = 683,040.21
  5. Step 5: Solve for x
    x = 683,040.21/881.40
  6. Step 6: Final answer
    x = 774.95

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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.