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Finding the Fourth Proportional to 1,398.63, 1,930.01 and 809.21

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Solution

The fourth proportional to 1,398.63, 1,930.01 and 809.21 is: 1,116.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,398.63 : 1,930.01 = 809.21 : x
  2. Step 2: Convert to fraction form
    1,398.63/1,930.01 = 809.21/x
  3. Step 3: Cross multiply
    1,398.63x = 1,930.01 × 809.21
  4. Step 4: Simplify right side
    1,398.63x = 1,561,784.17
  5. Step 5: Solve for x
    x = 1,561,784.17/1,398.63
  6. Step 6: Final answer
    x = 1,116.65

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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.