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Finding the Fourth Proportional to 642.18, 889.79 and 628.35

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Solution

The fourth proportional to 642.18, 889.79 and 628.35 is: 870.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.18 : 889.79 = 628.35 : x
  2. Step 2: Convert to fraction form
    642.18/889.79 = 628.35/x
  3. Step 3: Cross multiply
    642.18x = 889.79 × 628.35
  4. Step 4: Simplify right side
    642.18x = 559,096.40
  5. Step 5: Solve for x
    x = 559,096.40/642.18
  6. Step 6: Final answer
    x = 870.62

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.