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Finding the Fourth Proportional to 1,260.80, 1,889.28 and 611.20

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Solution

The fourth proportional to 1,260.80, 1,889.28 and 611.20 is: 915.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,260.80 : 1,889.28 = 611.20 : x
  2. Step 2: Convert to fraction form
    1,260.80/1,889.28 = 611.20/x
  3. Step 3: Cross multiply
    1,260.80x = 1,889.28 × 611.20
  4. Step 4: Simplify right side
    1,260.80x = 1,154,727.94
  5. Step 5: Solve for x
    x = 1,154,727.94/1,260.80
  6. Step 6: Final answer
    x = 915.87

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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.