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Finding the Fourth Proportional to 918.42, 1,377.90 and 398.21

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Solution

The fourth proportional to 918.42, 1,377.90 and 398.21 is: 597.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.42 : 1,377.90 = 398.21 : x
  2. Step 2: Convert to fraction form
    918.42/1,377.90 = 398.21/x
  3. Step 3: Cross multiply
    918.42x = 1,377.90 × 398.21
  4. Step 4: Simplify right side
    918.42x = 548,686.67
  5. Step 5: Solve for x
    x = 548,686.67/918.42
  6. Step 6: Final answer
    x = 597.42

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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.