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Finding the Fourth Proportional to 761.25, 1,145.70 and 685.79

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Solution

The fourth proportional to 761.25, 1,145.70 and 685.79 is: 1,032.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    761.25 : 1,145.70 = 685.79 : x
  2. Step 2: Convert to fraction form
    761.25/1,145.70 = 685.79/x
  3. Step 3: Cross multiply
    761.25x = 1,145.70 × 685.79
  4. Step 4: Simplify right side
    761.25x = 785,709.60
  5. Step 5: Solve for x
    x = 785,709.60/761.25
  6. Step 6: Final answer
    x = 1,032.13

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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.