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Finding the Fourth Proportional to 645.76, 890.76 and 413.20

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Solution

The fourth proportional to 645.76, 890.76 and 413.20 is: 569.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.76 : 890.76 = 413.20 : x
  2. Step 2: Convert to fraction form
    645.76/890.76 = 413.20/x
  3. Step 3: Cross multiply
    645.76x = 890.76 × 413.20
  4. Step 4: Simplify right side
    645.76x = 368,062.03
  5. Step 5: Solve for x
    x = 368,062.03/645.76
  6. Step 6: Final answer
    x = 569.97

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.