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Finding the Fourth Proportional to 1,005.80, 1,387.86 and 656.60

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Solution

The fourth proportional to 1,005.80, 1,387.86 and 656.60 is: 906.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.80 : 1,387.86 = 656.60 : x
  2. Step 2: Convert to fraction form
    1,005.80/1,387.86 = 656.60/x
  3. Step 3: Cross multiply
    1,005.80x = 1,387.86 × 656.60
  4. Step 4: Simplify right side
    1,005.80x = 911,268.88
  5. Step 5: Solve for x
    x = 911,268.88/1,005.80
  6. Step 6: Final answer
    x = 906.01

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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.