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Finding the Fourth Proportional to 913.55, 1,369.61 and 420.28

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Solution

The fourth proportional to 913.55, 1,369.61 and 420.28 is: 630.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.55 : 1,369.61 = 420.28 : x
  2. Step 2: Convert to fraction form
    913.55/1,369.61 = 420.28/x
  3. Step 3: Cross multiply
    913.55x = 1,369.61 × 420.28
  4. Step 4: Simplify right side
    913.55x = 575,614.17
  5. Step 5: Solve for x
    x = 575,614.17/913.55
  6. Step 6: Final answer
    x = 630.09

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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.