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Finding the Fourth Proportional to 1,390.72, 2,084.64 and 659.74

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Solution

The fourth proportional to 1,390.72, 2,084.64 and 659.74 is: 988.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.72 : 2,084.64 = 659.74 : x
  2. Step 2: Convert to fraction form
    1,390.72/2,084.64 = 659.74/x
  3. Step 3: Cross multiply
    1,390.72x = 2,084.64 × 659.74
  4. Step 4: Simplify right side
    1,390.72x = 1,375,320.39
  5. Step 5: Solve for x
    x = 1,375,320.39/1,390.72
  6. Step 6: Final answer
    x = 988.93

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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.