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Finding the Fourth Proportional to 1,200.40, 1,798.20 and 686.80

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Solution

The fourth proportional to 1,200.40, 1,798.20 and 686.80 is: 1,028.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,200.40 : 1,798.20 = 686.80 : x
  2. Step 2: Convert to fraction form
    1,200.40/1,798.20 = 686.80/x
  3. Step 3: Cross multiply
    1,200.40x = 1,798.20 × 686.80
  4. Step 4: Simplify right side
    1,200.40x = 1,235,003.76
  5. Step 5: Solve for x
    x = 1,235,003.76/1,200.40
  6. Step 6: Final answer
    x = 1,028.83

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1.5x scale

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.