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Finding the Fourth Proportional to 1,371.17, 1,891.95 and 781.69

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Solution

The fourth proportional to 1,371.17, 1,891.95 and 781.69 is: 1,078.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,371.17 : 1,891.95 = 781.69 : x
  2. Step 2: Convert to fraction form
    1,371.17/1,891.95 = 781.69/x
  3. Step 3: Cross multiply
    1,371.17x = 1,891.95 × 781.69
  4. Step 4: Simplify right side
    1,371.17x = 1,478,918.40
  5. Step 5: Solve for x
    x = 1,478,918.40/1,371.17
  6. Step 6: Final answer
    x = 1,078.58

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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.