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Finding the Fourth Proportional to 1,223.70, 1,688 and 891.74

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Solution

The fourth proportional to 1,223.70, 1,688 and 891.74 is: 1,230.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,223.70 : 1,688 = 891.74 : x
  2. Step 2: Convert to fraction form
    1,223.70/1,688 = 891.74/x
  3. Step 3: Cross multiply
    1,223.70x = 1,688 × 891.74
  4. Step 4: Simplify right side
    1,223.70x = 1,505,257.12
  5. Step 5: Solve for x
    x = 1,505,257.12/1,223.70
  6. Step 6: Final answer
    x = 1,230.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.