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Finding the Fourth Proportional to 642.90, 964.35 and 411.90

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Solution

The fourth proportional to 642.90, 964.35 and 411.90 is: 617.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.90 : 964.35 = 411.90 : x
  2. Step 2: Convert to fraction form
    642.90/964.35 = 411.90/x
  3. Step 3: Cross multiply
    642.90x = 964.35 × 411.90
  4. Step 4: Simplify right side
    642.90x = 397,208.88
  5. Step 5: Solve for x
    x = 397,208.88/642.90
  6. Step 6: Final answer
    x = 617.84

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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.