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Finding the Fourth Proportional to 645.16, 889.38 and 489.64

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Solution

The fourth proportional to 645.16, 889.38 and 489.64 is: 674.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.16 : 889.38 = 489.64 : x
  2. Step 2: Convert to fraction form
    645.16/889.38 = 489.64/x
  3. Step 3: Cross multiply
    645.16x = 889.38 × 489.64
  4. Step 4: Simplify right side
    645.16x = 435,476.02
  5. Step 5: Solve for x
    x = 435,476.02/645.16
  6. Step 6: Final answer
    x = 674.99

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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.