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Finding the Fourth Proportional to 1,128.50, 1,690.24 and 511.28

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Solution

The fourth proportional to 1,128.50, 1,690.24 and 511.28 is: 765.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.50 : 1,690.24 = 511.28 : x
  2. Step 2: Convert to fraction form
    1,128.50/1,690.24 = 511.28/x
  3. Step 3: Cross multiply
    1,128.50x = 1,690.24 × 511.28
  4. Step 4: Simplify right side
    1,128.50x = 864,185.91
  5. Step 5: Solve for x
    x = 864,185.91/1,128.50
  6. Step 6: Final answer
    x = 765.78

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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.