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Finding the Fourth Proportional to 868.60, 1,299.30 and 782.20

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Solution

The fourth proportional to 868.60, 1,299.30 and 782.20 is: 1,170.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    868.60 : 1,299.30 = 782.20 : x
  2. Step 2: Convert to fraction form
    868.60/1,299.30 = 782.20/x
  3. Step 3: Cross multiply
    868.60x = 1,299.30 × 782.20
  4. Step 4: Simplify right side
    868.60x = 1,016,312.46
  5. Step 5: Solve for x
    x = 1,016,312.46/868.60
  6. Step 6: Final answer
    x = 1,170.06

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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.