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Finding the Fourth Proportional to 679.68, 1,017.90 and 419.81

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Solution

The fourth proportional to 679.68, 1,017.90 and 419.81 is: 628.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.68 : 1,017.90 = 419.81 : x
  2. Step 2: Convert to fraction form
    679.68/1,017.90 = 419.81/x
  3. Step 3: Cross multiply
    679.68x = 1,017.90 × 419.81
  4. Step 4: Simplify right side
    679.68x = 427,319.51
  5. Step 5: Solve for x
    x = 427,319.51/679.68
  6. Step 6: Final answer
    x = 628.71

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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.