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Finding the Fourth Proportional to 620.64, 929.52 and 428.40

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Solution

The fourth proportional to 620.64, 929.52 and 428.40 is: 641.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.64 : 929.52 = 428.40 : x
  2. Step 2: Convert to fraction form
    620.64/929.52 = 428.40/x
  3. Step 3: Cross multiply
    620.64x = 929.52 × 428.40
  4. Step 4: Simplify right side
    620.64x = 398,206.37
  5. Step 5: Solve for x
    x = 398,206.37/620.64
  6. Step 6: Final answer
    x = 641.61

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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.