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Finding the Fourth Proportional to 611.25, 914.94 and 428.10

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Solution

The fourth proportional to 611.25, 914.94 and 428.10 is: 640.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.25 : 914.94 = 428.10 : x
  2. Step 2: Convert to fraction form
    611.25/914.94 = 428.10/x
  3. Step 3: Cross multiply
    611.25x = 914.94 × 428.10
  4. Step 4: Simplify right side
    611.25x = 391,685.81
  5. Step 5: Solve for x
    x = 391,685.81/611.25
  6. Step 6: Final answer
    x = 640.79

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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.