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Finding the Fourth Proportional to 309.12, 428.70 and 300.12

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Solution

The fourth proportional to 309.12, 428.70 and 300.12 is: 416.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.12 : 428.70 = 300.12 : x
  2. Step 2: Convert to fraction form
    309.12/428.70 = 300.12/x
  3. Step 3: Cross multiply
    309.12x = 428.70 × 300.12
  4. Step 4: Simplify right side
    309.12x = 128,661.44
  5. Step 5: Solve for x
    x = 128,661.44/309.12
  6. Step 6: Final answer
    x = 416.22

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.