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Finding the Fourth Proportional to 428.24, 642.45 and 135.77

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Solution

The fourth proportional to 428.24, 642.45 and 135.77 is: 203.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.24 : 642.45 = 135.77 : x
  2. Step 2: Convert to fraction form
    428.24/642.45 = 135.77/x
  3. Step 3: Cross multiply
    428.24x = 642.45 × 135.77
  4. Step 4: Simplify right side
    428.24x = 87,222.22
  5. Step 5: Solve for x
    x = 87,222.22/428.24
  6. Step 6: Final answer
    x = 203.68

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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.