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Finding the Fourth Proportional to 1,189.07, 1,640.80 and 691.70

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Solution

The fourth proportional to 1,189.07, 1,640.80 and 691.70 is: 954.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,189.07 : 1,640.80 = 691.70 : x
  2. Step 2: Convert to fraction form
    1,189.07/1,640.80 = 691.70/x
  3. Step 3: Cross multiply
    1,189.07x = 1,640.80 × 691.70
  4. Step 4: Simplify right side
    1,189.07x = 1,134,931.43
  5. Step 5: Solve for x
    x = 1,134,931.43/1,189.07
  6. Step 6: Final answer
    x = 954.47

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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.