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Finding the Fourth Proportional to 857.40, 1,288.80 and 792.60

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Solution

The fourth proportional to 857.40, 1,288.80 and 792.60 is: 1,191.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.40 : 1,288.80 = 792.60 : x
  2. Step 2: Convert to fraction form
    857.40/1,288.80 = 792.60/x
  3. Step 3: Cross multiply
    857.40x = 1,288.80 × 792.60
  4. Step 4: Simplify right side
    857.40x = 1,021,502.88
  5. Step 5: Solve for x
    x = 1,021,502.88/857.40
  6. Step 6: Final answer
    x = 1,191.40

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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.