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Finding the Fourth Proportional to 1,245, 1,718.10 and 685.45

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Solution

The fourth proportional to 1,245, 1,718.10 and 685.45 is: 945.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,245 : 1,718.10 = 685.45 : x
  2. Step 2: Convert to fraction form
    1,245/1,718.10 = 685.45/x
  3. Step 3: Cross multiply
    1,245x = 1,718.10 × 685.45
  4. Step 4: Simplify right side
    1,245x = 1,177,671.65
  5. Step 5: Solve for x
    x = 1,177,671.65/1,245
  6. Step 6: Final answer
    x = 945.92

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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.