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Finding the Fourth Proportional to 645.85, 969.35 and 425.86

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Solution

The fourth proportional to 645.85, 969.35 and 425.86 is: 639.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.85 : 969.35 = 425.86 : x
  2. Step 2: Convert to fraction form
    645.85/969.35 = 425.86/x
  3. Step 3: Cross multiply
    645.85x = 969.35 × 425.86
  4. Step 4: Simplify right side
    645.85x = 412,802.84
  5. Step 5: Solve for x
    x = 412,802.84/645.85
  6. Step 6: Final answer
    x = 639.16

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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.