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Finding the Fourth Proportional to 1,438.65, 1,985.36 and 809.19

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Solution

The fourth proportional to 1,438.65, 1,985.36 and 809.19 is: 1,116.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,438.65 : 1,985.36 = 809.19 : x
  2. Step 2: Convert to fraction form
    1,438.65/1,985.36 = 809.19/x
  3. Step 3: Cross multiply
    1,438.65x = 1,985.36 × 809.19
  4. Step 4: Simplify right side
    1,438.65x = 1,606,529.41
  5. Step 5: Solve for x
    x = 1,606,529.41/1,438.65
  6. Step 6: Final answer
    x = 1,116.69

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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.