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Finding the Fourth Proportional to 1,387.11, 1,915.11 and 889.95

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Solution

The fourth proportional to 1,387.11, 1,915.11 and 889.95 is: 1,228.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.11 : 1,915.11 = 889.95 : x
  2. Step 2: Convert to fraction form
    1,387.11/1,915.11 = 889.95/x
  3. Step 3: Cross multiply
    1,387.11x = 1,915.11 × 889.95
  4. Step 4: Simplify right side
    1,387.11x = 1,704,352.14
  5. Step 5: Solve for x
    x = 1,704,352.14/1,387.11
  6. Step 6: Final answer
    x = 1,228.71

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1.5x scale

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.