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Finding the Fourth Proportional to 815.40, 1,125.36 and 520.85

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Solution

The fourth proportional to 815.40, 1,125.36 and 520.85 is: 718.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.40 : 1,125.36 = 520.85 : x
  2. Step 2: Convert to fraction form
    815.40/1,125.36 = 520.85/x
  3. Step 3: Cross multiply
    815.40x = 1,125.36 × 520.85
  4. Step 4: Simplify right side
    815.40x = 586,146.57
  5. Step 5: Solve for x
    x = 586,146.57/815.40
  6. Step 6: Final answer
    x = 718.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.