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Finding the Fourth Proportional to 428.63, 642.94 and 140.06

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Solution

The fourth proportional to 428.63, 642.94 and 140.06 is: 210.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.63 : 642.94 = 140.06 : x
  2. Step 2: Convert to fraction form
    428.63/642.94 = 140.06/x
  3. Step 3: Cross multiply
    428.63x = 642.94 × 140.06
  4. Step 4: Simplify right side
    428.63x = 90,051.43
  5. Step 5: Solve for x
    x = 90,051.43/428.63
  6. Step 6: Final answer
    x = 210.09

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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.