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Finding the Fourth Proportional to 642.78, 965.07 and 613.41

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Solution

The fourth proportional to 642.78, 965.07 and 613.41 is: 920.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.78 : 965.07 = 613.41 : x
  2. Step 2: Convert to fraction form
    642.78/965.07 = 613.41/x
  3. Step 3: Cross multiply
    642.78x = 965.07 × 613.41
  4. Step 4: Simplify right side
    642.78x = 591,989.51
  5. Step 5: Solve for x
    x = 591,989.51/642.78
  6. Step 6: Final answer
    x = 920.99

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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.