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Finding the Fourth Proportional to 911.21, 1,366.95 and 478.40

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Solution

The fourth proportional to 911.21, 1,366.95 and 478.40 is: 717.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.21 : 1,366.95 = 478.40 : x
  2. Step 2: Convert to fraction form
    911.21/1,366.95 = 478.40/x
  3. Step 3: Cross multiply
    911.21x = 1,366.95 × 478.40
  4. Step 4: Simplify right side
    911.21x = 653,948.88
  5. Step 5: Solve for x
    x = 653,948.88/911.21
  6. Step 6: Final answer
    x = 717.67

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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.