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Finding the Fourth Proportional to 612.71, 918.14 and 428.23

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Solution

The fourth proportional to 612.71, 918.14 and 428.23 is: 641.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.71 : 918.14 = 428.23 : x
  2. Step 2: Convert to fraction form
    612.71/918.14 = 428.23/x
  3. Step 3: Cross multiply
    612.71x = 918.14 × 428.23
  4. Step 4: Simplify right side
    612.71x = 393,175.09
  5. Step 5: Solve for x
    x = 393,175.09/612.71
  6. Step 6: Final answer
    x = 641.70

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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.