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Finding the Fourth Proportional to 1,390.32, 2,085.60 and 659.52

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Solution

The fourth proportional to 1,390.32, 2,085.60 and 659.52 is: 989.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.32 : 2,085.60 = 659.52 : x
  2. Step 2: Convert to fraction form
    1,390.32/2,085.60 = 659.52/x
  3. Step 3: Cross multiply
    1,390.32x = 2,085.60 × 659.52
  4. Step 4: Simplify right side
    1,390.32x = 1,375,494.91
  5. Step 5: Solve for x
    x = 1,375,494.91/1,390.32
  6. Step 6: Final answer
    x = 989.34

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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.