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Finding the Fourth Proportional to 660.74, 911.39 and 398.50

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Solution

The fourth proportional to 660.74, 911.39 and 398.50 is: 549.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.74 : 911.39 = 398.50 : x
  2. Step 2: Convert to fraction form
    660.74/911.39 = 398.50/x
  3. Step 3: Cross multiply
    660.74x = 911.39 × 398.50
  4. Step 4: Simplify right side
    660.74x = 363,188.92
  5. Step 5: Solve for x
    x = 363,188.92/660.74
  6. Step 6: Final answer
    x = 549.67

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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.