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Finding the Fourth Proportional to 645.76, 891.18 and 383.80

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Solution

The fourth proportional to 645.76, 891.18 and 383.80 is: 529.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.76 : 891.18 = 383.80 : x
  2. Step 2: Convert to fraction form
    645.76/891.18 = 383.80/x
  3. Step 3: Cross multiply
    645.76x = 891.18 × 383.80
  4. Step 4: Simplify right side
    645.76x = 342,034.88
  5. Step 5: Solve for x
    x = 342,034.88/645.76
  6. Step 6: Final answer
    x = 529.66

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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.