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Finding the Fourth Proportional to 1,218.59, 1,680.70 and 820.67

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Solution

The fourth proportional to 1,218.59, 1,680.70 and 820.67 is: 1,131.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.59 : 1,680.70 = 820.67 : x
  2. Step 2: Convert to fraction form
    1,218.59/1,680.70 = 820.67/x
  3. Step 3: Cross multiply
    1,218.59x = 1,680.70 × 820.67
  4. Step 4: Simplify right side
    1,218.59x = 1,379,300.07
  5. Step 5: Solve for x
    x = 1,379,300.07/1,218.59
  6. Step 6: Final answer
    x = 1,131.88

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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.