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Finding the Fourth Proportional to 1,428.80, 2,142.72 and 659.20

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Solution

The fourth proportional to 1,428.80, 2,142.72 and 659.20 is: 988.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.80 : 2,142.72 = 659.20 : x
  2. Step 2: Convert to fraction form
    1,428.80/2,142.72 = 659.20/x
  3. Step 3: Cross multiply
    1,428.80x = 2,142.72 × 659.20
  4. Step 4: Simplify right side
    1,428.80x = 1,412,481.02
  5. Step 5: Solve for x
    x = 1,412,481.02/1,428.80
  6. Step 6: Final answer
    x = 988.58

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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.