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Finding the Fourth Proportional to 1,291, 1,780.38 and 995.80

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Solution

The fourth proportional to 1,291, 1,780.38 and 995.80 is: 1,373.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,291 : 1,780.38 = 995.80 : x
  2. Step 2: Convert to fraction form
    1,291/1,780.38 = 995.80/x
  3. Step 3: Cross multiply
    1,291x = 1,780.38 × 995.80
  4. Step 4: Simplify right side
    1,291x = 1,772,902.40
  5. Step 5: Solve for x
    x = 1,772,902.40/1,291
  6. Step 6: Final answer
    x = 1,373.28

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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.