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Finding the Fourth Proportional to 913.87, 1,369.57 and 420

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Solution

The fourth proportional to 913.87, 1,369.57 and 420 is: 629.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.87 : 1,369.57 = 420 : x
  2. Step 2: Convert to fraction form
    913.87/1,369.57 = 420/x
  3. Step 3: Cross multiply
    913.87x = 1,369.57 × 420
  4. Step 4: Simplify right side
    913.87x = 575,219.40
  5. Step 5: Solve for x
    x = 575,219.40/913.87
  6. Step 6: Final answer
    x = 629.43

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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.