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Finding the Fourth Proportional to 991.17, 1,486.73 and 260.80

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Solution

The fourth proportional to 991.17, 1,486.73 and 260.80 is: 391.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.17 : 1,486.73 = 260.80 : x
  2. Step 2: Convert to fraction form
    991.17/1,486.73 = 260.80/x
  3. Step 3: Cross multiply
    991.17x = 1,486.73 × 260.80
  4. Step 4: Simplify right side
    991.17x = 387,736.12
  5. Step 5: Solve for x
    x = 387,736.12/991.17
  6. Step 6: Final answer
    x = 391.19

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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.