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Finding the Fourth Proportional to 1,128.06, 1,689.85 and 688.77

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Solution

The fourth proportional to 1,128.06, 1,689.85 and 688.77 is: 1,031.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.06 : 1,689.85 = 688.77 : x
  2. Step 2: Convert to fraction form
    1,128.06/1,689.85 = 688.77/x
  3. Step 3: Cross multiply
    1,128.06x = 1,689.85 × 688.77
  4. Step 4: Simplify right side
    1,128.06x = 1,163,917.98
  5. Step 5: Solve for x
    x = 1,163,917.98/1,128.06
  6. Step 6: Final answer
    x = 1,031.79

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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.