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Finding the Fourth Proportional to 1,856, 2,785.28 and 640

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Solution

The fourth proportional to 1,856, 2,785.28 and 640 is: 960.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,856 : 2,785.28 = 640 : x
  2. Step 2: Convert to fraction form
    1,856/2,785.28 = 640/x
  3. Step 3: Cross multiply
    1,856x = 2,785.28 × 640
  4. Step 4: Simplify right side
    1,856x = 1,782,579.20
  5. Step 5: Solve for x
    x = 1,782,579.20/1,856
  6. Step 6: Final answer
    x = 960.44

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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.