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Finding the Fourth Proportional to 920.80, 1,380.40 and 555.20

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Solution

The fourth proportional to 920.80, 1,380.40 and 555.20 is: 832.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.80 : 1,380.40 = 555.20 : x
  2. Step 2: Convert to fraction form
    920.80/1,380.40 = 555.20/x
  3. Step 3: Cross multiply
    920.80x = 1,380.40 × 555.20
  4. Step 4: Simplify right side
    920.80x = 766,398.08
  5. Step 5: Solve for x
    x = 766,398.08/920.80
  6. Step 6: Final answer
    x = 832.32

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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.