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Finding the Fourth Proportional to 642.40, 963.61 and 155.45

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Solution

The fourth proportional to 642.40, 963.61 and 155.45 is: 233.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.40 : 963.61 = 155.45 : x
  2. Step 2: Convert to fraction form
    642.40/963.61 = 155.45/x
  3. Step 3: Cross multiply
    642.40x = 963.61 × 155.45
  4. Step 4: Simplify right side
    642.40x = 149,796.21
  5. Step 5: Solve for x
    x = 149,796.21/642.40
  6. Step 6: Final answer
    x = 233.18

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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.