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Finding the Fourth Proportional to 818.70, 1,218.80 and 813.84

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Solution

The fourth proportional to 818.70, 1,218.80 and 813.84 is: 1,211.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.70 : 1,218.80 = 813.84 : x
  2. Step 2: Convert to fraction form
    818.70/1,218.80 = 813.84/x
  3. Step 3: Cross multiply
    818.70x = 1,218.80 × 813.84
  4. Step 4: Simplify right side
    818.70x = 991,903.36
  5. Step 5: Solve for x
    x = 991,903.36/818.70
  6. Step 6: Final answer
    x = 1,211.55

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.