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Finding the Fourth Proportional to 1,128.24, 1,689.12 and 838.80

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Solution

The fourth proportional to 1,128.24, 1,689.12 and 838.80 is: 1,255.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.24 : 1,689.12 = 838.80 : x
  2. Step 2: Convert to fraction form
    1,128.24/1,689.12 = 838.80/x
  3. Step 3: Cross multiply
    1,128.24x = 1,689.12 × 838.80
  4. Step 4: Simplify right side
    1,128.24x = 1,416,833.86
  5. Step 5: Solve for x
    x = 1,416,833.86/1,128.24
  6. Step 6: Final answer
    x = 1,255.79

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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.