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Finding the Fourth Proportional to 1,398.72, 1,930.08 and 809.16

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Solution

The fourth proportional to 1,398.72, 1,930.08 and 809.16 is: 1,116.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,398.72 : 1,930.08 = 809.16 : x
  2. Step 2: Convert to fraction form
    1,398.72/1,930.08 = 809.16/x
  3. Step 3: Cross multiply
    1,398.72x = 1,930.08 × 809.16
  4. Step 4: Simplify right side
    1,398.72x = 1,561,743.53
  5. Step 5: Solve for x
    x = 1,561,743.53/1,398.72
  6. Step 6: Final answer
    x = 1,116.55

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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.