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Finding the Fourth Proportional to 428.50, 642.78 and 154.67

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Solution

The fourth proportional to 428.50, 642.78 and 154.67 is: 232.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.50 : 642.78 = 154.67 : x
  2. Step 2: Convert to fraction form
    428.50/642.78 = 154.67/x
  3. Step 3: Cross multiply
    428.50x = 642.78 × 154.67
  4. Step 4: Simplify right side
    428.50x = 99,420.39
  5. Step 5: Solve for x
    x = 99,420.39/428.50
  6. Step 6: Final answer
    x = 232.02

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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.