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Finding the Fourth Proportional to 772.20, 1,158.30 and 687.15

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Solution

The fourth proportional to 772.20, 1,158.30 and 687.15 is: 1,030.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    772.20 : 1,158.30 = 687.15 : x
  2. Step 2: Convert to fraction form
    772.20/1,158.30 = 687.15/x
  3. Step 3: Cross multiply
    772.20x = 1,158.30 × 687.15
  4. Step 4: Simplify right side
    772.20x = 795,925.85
  5. Step 5: Solve for x
    x = 795,925.85/772.20
  6. Step 6: Final answer
    x = 1,030.73

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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.