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Finding the Fourth Proportional to 1,020.64, 1,408.80 and 688.84

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Solution

The fourth proportional to 1,020.64, 1,408.80 and 688.84 is: 950.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,020.64 : 1,408.80 = 688.84 : x
  2. Step 2: Convert to fraction form
    1,020.64/1,408.80 = 688.84/x
  3. Step 3: Cross multiply
    1,020.64x = 1,408.80 × 688.84
  4. Step 4: Simplify right side
    1,020.64x = 970,437.79
  5. Step 5: Solve for x
    x = 970,437.79/1,020.64
  6. Step 6: Final answer
    x = 950.81

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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.