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Finding the Fourth Proportional to 1,211.55, 1,672.10 and 818.55

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Solution

The fourth proportional to 1,211.55, 1,672.10 and 818.55 is: 1,129.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,211.55 : 1,672.10 = 818.55 : x
  2. Step 2: Convert to fraction form
    1,211.55/1,672.10 = 818.55/x
  3. Step 3: Cross multiply
    1,211.55x = 1,672.10 × 818.55
  4. Step 4: Simplify right side
    1,211.55x = 1,368,693.36
  5. Step 5: Solve for x
    x = 1,368,693.36/1,211.55
  6. Step 6: Final answer
    x = 1,129.70

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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.