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Finding the Fourth Proportional to 690.80, 1,040.93 and 571.72

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Solution

The fourth proportional to 690.80, 1,040.93 and 571.72 is: 861.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.80 : 1,040.93 = 571.72 : x
  2. Step 2: Convert to fraction form
    690.80/1,040.93 = 571.72/x
  3. Step 3: Cross multiply
    690.80x = 1,040.93 × 571.72
  4. Step 4: Simplify right side
    690.80x = 595,120.50
  5. Step 5: Solve for x
    x = 595,120.50/690.80
  6. Step 6: Final answer
    x = 861.49

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.