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Finding the Fourth Proportional to 1,128.60, 1,689.12 and 641.52

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Solution

The fourth proportional to 1,128.60, 1,689.12 and 641.52 is: 960.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.60 : 1,689.12 = 641.52 : x
  2. Step 2: Convert to fraction form
    1,128.60/1,689.12 = 641.52/x
  3. Step 3: Cross multiply
    1,128.60x = 1,689.12 × 641.52
  4. Step 4: Simplify right side
    1,128.60x = 1,083,604.26
  5. Step 5: Solve for x
    x = 1,083,604.26/1,128.60
  6. Step 6: Final answer
    x = 960.13

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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.