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Finding the Fourth Proportional to 985.50, 1,478.52 and 408.38

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Solution

The fourth proportional to 985.50, 1,478.52 and 408.38 is: 612.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.50 : 1,478.52 = 408.38 : x
  2. Step 2: Convert to fraction form
    985.50/1,478.52 = 408.38/x
  3. Step 3: Cross multiply
    985.50x = 1,478.52 × 408.38
  4. Step 4: Simplify right side
    985.50x = 603,790.61
  5. Step 5: Solve for x
    x = 603,790.61/985.50
  6. Step 6: Final answer
    x = 612.67

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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.