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Finding the Fourth Proportional to 1,389.60, 2,085.42 and 659.17

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Solution

The fourth proportional to 1,389.60, 2,085.42 and 659.17 is: 989.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.60 : 2,085.42 = 659.17 : x
  2. Step 2: Convert to fraction form
    1,389.60/2,085.42 = 659.17/x
  3. Step 3: Cross multiply
    1,389.60x = 2,085.42 × 659.17
  4. Step 4: Simplify right side
    1,389.60x = 1,374,649.87
  5. Step 5: Solve for x
    x = 1,374,649.87/1,389.60
  6. Step 6: Final answer
    x = 989.24

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.