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Finding the Fourth Proportional to 871.59, 1,313.38 and 720.90

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Solution

The fourth proportional to 871.59, 1,313.38 and 720.90 is: 1,086.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.59 : 1,313.38 = 720.90 : x
  2. Step 2: Convert to fraction form
    871.59/1,313.38 = 720.90/x
  3. Step 3: Cross multiply
    871.59x = 1,313.38 × 720.90
  4. Step 4: Simplify right side
    871.59x = 946,813.50
  5. Step 5: Solve for x
    x = 946,813.50/871.59
  6. Step 6: Final answer
    x = 1,086.31

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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.