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Finding the Fourth Proportional to 840.68, 1,161.53 and 665.00

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Solution

The fourth proportional to 840.68, 1,161.53 and 665.00 is: 918.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.68 : 1,161.53 = 665.00 : x
  2. Step 2: Convert to fraction form
    840.68/1,161.53 = 665.00/x
  3. Step 3: Cross multiply
    840.68x = 1,161.53 × 665.00
  4. Step 4: Simplify right side
    840.68x = 772,413.30
  5. Step 5: Solve for x
    x = 772,413.30/840.68
  6. Step 6: Final answer
    x = 918.79

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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.