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Finding the Fourth Proportional to 1,438.67, 1,985.40 and 809.19

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Solution

The fourth proportional to 1,438.67, 1,985.40 and 809.19 is: 1,116.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,438.67 : 1,985.40 = 809.19 : x
  2. Step 2: Convert to fraction form
    1,438.67/1,985.40 = 809.19/x
  3. Step 3: Cross multiply
    1,438.67x = 1,985.40 × 809.19
  4. Step 4: Simplify right side
    1,438.67x = 1,606,565.83
  5. Step 5: Solve for x
    x = 1,606,565.83/1,438.67
  6. Step 6: Final answer
    x = 1,116.70

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Double scale
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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.