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Finding the Fourth Proportional to 921.20, 1,381.80 and 556.70

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Solution

The fourth proportional to 921.20, 1,381.80 and 556.70 is: 835.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.20 : 1,381.80 = 556.70 : x
  2. Step 2: Convert to fraction form
    921.20/1,381.80 = 556.70/x
  3. Step 3: Cross multiply
    921.20x = 1,381.80 × 556.70
  4. Step 4: Simplify right side
    921.20x = 769,248.06
  5. Step 5: Solve for x
    x = 769,248.06/921.20
  6. Step 6: Final answer
    x = 835.05

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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.