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Finding the Fourth Proportional to 898.78, 1,239.48 and 772.70

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Solution

The fourth proportional to 898.78, 1,239.48 and 772.70 is: 1,065.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    898.78 : 1,239.48 = 772.70 : x
  2. Step 2: Convert to fraction form
    898.78/1,239.48 = 772.70/x
  3. Step 3: Cross multiply
    898.78x = 1,239.48 × 772.70
  4. Step 4: Simplify right side
    898.78x = 957,746.20
  5. Step 5: Solve for x
    x = 957,746.20/898.78
  6. Step 6: Final answer
    x = 1,065.61

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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.