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Finding the Fourth Proportional to 1,188.79, 1,640.64 and 664.99

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Solution

The fourth proportional to 1,188.79, 1,640.64 and 664.99 is: 917.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,188.79 : 1,640.64 = 664.99 : x
  2. Step 2: Convert to fraction form
    1,188.79/1,640.64 = 664.99/x
  3. Step 3: Cross multiply
    1,188.79x = 1,640.64 × 664.99
  4. Step 4: Simplify right side
    1,188.79x = 1,091,009.19
  5. Step 5: Solve for x
    x = 1,091,009.19/1,188.79
  6. Step 6: Final answer
    x = 917.75

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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.