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Finding the Fourth Proportional to 1,220.80, 1,684.80 and 755.20

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Solution

The fourth proportional to 1,220.80, 1,684.80 and 755.20 is: 1,042.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.80 : 1,684.80 = 755.20 : x
  2. Step 2: Convert to fraction form
    1,220.80/1,684.80 = 755.20/x
  3. Step 3: Cross multiply
    1,220.80x = 1,684.80 × 755.20
  4. Step 4: Simplify right side
    1,220.80x = 1,272,360.96
  5. Step 5: Solve for x
    x = 1,272,360.96/1,220.80
  6. Step 6: Final answer
    x = 1,042.24

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.