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Finding the Fourth Proportional to 813.81, 1,123.50 and 499.15

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Solution

The fourth proportional to 813.81, 1,123.50 and 499.15 is: 689.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.81 : 1,123.50 = 499.15 : x
  2. Step 2: Convert to fraction form
    813.81/1,123.50 = 499.15/x
  3. Step 3: Cross multiply
    813.81x = 1,123.50 × 499.15
  4. Step 4: Simplify right side
    813.81x = 560,795.03
  5. Step 5: Solve for x
    x = 560,795.03/813.81
  6. Step 6: Final answer
    x = 689.10

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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.