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Finding the Fourth Proportional to 728.20, 1,091.82 and 651.40

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Solution

The fourth proportional to 728.20, 1,091.82 and 651.40 is: 976.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.20 : 1,091.82 = 651.40 : x
  2. Step 2: Convert to fraction form
    728.20/1,091.82 = 651.40/x
  3. Step 3: Cross multiply
    728.20x = 1,091.82 × 651.40
  4. Step 4: Simplify right side
    728.20x = 711,211.55
  5. Step 5: Solve for x
    x = 711,211.55/728.20
  6. Step 6: Final answer
    x = 976.67

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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.