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Finding the Fourth Proportional to 1,101.60, 1,661.40 and 986.40

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Solution

The fourth proportional to 1,101.60, 1,661.40 and 986.40 is: 1,487.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,101.60 : 1,661.40 = 986.40 : x
  2. Step 2: Convert to fraction form
    1,101.60/1,661.40 = 986.40/x
  3. Step 3: Cross multiply
    1,101.60x = 1,661.40 × 986.40
  4. Step 4: Simplify right side
    1,101.60x = 1,638,804.96
  5. Step 5: Solve for x
    x = 1,638,804.96/1,101.60
  6. Step 6: Final answer
    x = 1,487.66

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.