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Finding the Fourth Proportional to 815.79, 1,125.86 and 521.31

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Solution

The fourth proportional to 815.79, 1,125.86 and 521.31 is: 719.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.79 : 1,125.86 = 521.31 : x
  2. Step 2: Convert to fraction form
    815.79/1,125.86 = 521.31/x
  3. Step 3: Cross multiply
    815.79x = 1,125.86 × 521.31
  4. Step 4: Simplify right side
    815.79x = 586,919.47
  5. Step 5: Solve for x
    x = 586,919.47/815.79
  6. Step 6: Final answer
    x = 719.45

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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.