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Finding the Fourth Proportional to 612.90, 918 and 459

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Solution

The fourth proportional to 612.90, 918 and 459 is: 687.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.90 : 918 = 459 : x
  2. Step 2: Convert to fraction form
    612.90/918 = 459/x
  3. Step 3: Cross multiply
    612.90x = 918 × 459
  4. Step 4: Simplify right side
    612.90x = 421,362
  5. Step 5: Solve for x
    x = 421,362/612.90
  6. Step 6: Final answer
    x = 687.49

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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.