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Finding the Fourth Proportional to 1,986.86, 2,980.31 and 688.35

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Solution

The fourth proportional to 1,986.86, 2,980.31 and 688.35 is: 1,032.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,986.86 : 2,980.31 = 688.35 : x
  2. Step 2: Convert to fraction form
    1,986.86/2,980.31 = 688.35/x
  3. Step 3: Cross multiply
    1,986.86x = 2,980.31 × 688.35
  4. Step 4: Simplify right side
    1,986.86x = 2,051,498.11
  5. Step 5: Solve for x
    x = 2,051,498.11/1,986.86
  6. Step 6: Final answer
    x = 1,032.54

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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.