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Finding the Fourth Proportional to 1,399.13, 1,930.79 and 809.71

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Solution

The fourth proportional to 1,399.13, 1,930.79 and 809.71 is: 1,117.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,399.13 : 1,930.79 = 809.71 : x
  2. Step 2: Convert to fraction form
    1,399.13/1,930.79 = 809.71/x
  3. Step 3: Cross multiply
    1,399.13x = 1,930.79 × 809.71
  4. Step 4: Simplify right side
    1,399.13x = 1,563,377.17
  5. Step 5: Solve for x
    x = 1,563,377.17/1,399.13
  6. Step 6: Final answer
    x = 1,117.40

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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.