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Finding the Fourth Proportional to 679.21, 1,012.93 and 613.60

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Solution

The fourth proportional to 679.21, 1,012.93 and 613.60 is: 915.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.21 : 1,012.93 = 613.60 : x
  2. Step 2: Convert to fraction form
    679.21/1,012.93 = 613.60/x
  3. Step 3: Cross multiply
    679.21x = 1,012.93 × 613.60
  4. Step 4: Simplify right side
    679.21x = 621,529.78
  5. Step 5: Solve for x
    x = 621,529.78/679.21
  6. Step 6: Final answer
    x = 915.08

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.