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Finding the Fourth Proportional to 1,415.81, 2,123.84 and 428.55

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Solution

The fourth proportional to 1,415.81, 2,123.84 and 428.55 is: 642.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,415.81 : 2,123.84 = 428.55 : x
  2. Step 2: Convert to fraction form
    1,415.81/2,123.84 = 428.55/x
  3. Step 3: Cross multiply
    1,415.81x = 2,123.84 × 428.55
  4. Step 4: Simplify right side
    1,415.81x = 910,172.70
  5. Step 5: Solve for x
    x = 910,172.70/1,415.81
  6. Step 6: Final answer
    x = 642.87

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.