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Finding the Fourth Proportional to 981.95, 1,356.17 and 920.90

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Solution

The fourth proportional to 981.95, 1,356.17 and 920.90 is: 1,271.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.95 : 1,356.17 = 920.90 : x
  2. Step 2: Convert to fraction form
    981.95/1,356.17 = 920.90/x
  3. Step 3: Cross multiply
    981.95x = 1,356.17 × 920.90
  4. Step 4: Simplify right side
    981.95x = 1,248,895.74
  5. Step 5: Solve for x
    x = 1,248,895.74/981.95
  6. Step 6: Final answer
    x = 1,271.86

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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.