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Finding the Fourth Proportional to 813.74, 1,221.16 and 380.94

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Solution

The fourth proportional to 813.74, 1,221.16 and 380.94 is: 571.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.74 : 1,221.16 = 380.94 : x
  2. Step 2: Convert to fraction form
    813.74/1,221.16 = 380.94/x
  3. Step 3: Cross multiply
    813.74x = 1,221.16 × 380.94
  4. Step 4: Simplify right side
    813.74x = 465,188.69
  5. Step 5: Solve for x
    x = 465,188.69/813.74
  6. Step 6: Final answer
    x = 571.67

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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.