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Finding the Fourth Proportional to 921.16, 1,381.80 and 343.84

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Solution

The fourth proportional to 921.16, 1,381.80 and 343.84 is: 515.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.16 : 1,381.80 = 343.84 : x
  2. Step 2: Convert to fraction form
    921.16/1,381.80 = 343.84/x
  3. Step 3: Cross multiply
    921.16x = 1,381.80 × 343.84
  4. Step 4: Simplify right side
    921.16x = 475,118.11
  5. Step 5: Solve for x
    x = 475,118.11/921.16
  6. Step 6: Final answer
    x = 515.78

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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.