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Finding the Fourth Proportional to 1,986.79, 2,980.18 and 688.26

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Solution

The fourth proportional to 1,986.79, 2,980.18 and 688.26 is: 1,032.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,986.79 : 2,980.18 = 688.26 : x
  2. Step 2: Convert to fraction form
    1,986.79/2,980.18 = 688.26/x
  3. Step 3: Cross multiply
    1,986.79x = 2,980.18 × 688.26
  4. Step 4: Simplify right side
    1,986.79x = 2,051,125.58
  5. Step 5: Solve for x
    x = 2,051,125.58/1,986.79
  6. Step 6: Final answer
    x = 1,032.38

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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.