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Finding the Fourth Proportional to 1,131.50, 1,561.66 and 665.66

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Solution

The fourth proportional to 1,131.50, 1,561.66 and 665.66 is: 918.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,131.50 : 1,561.66 = 665.66 : x
  2. Step 2: Convert to fraction form
    1,131.50/1,561.66 = 665.66/x
  3. Step 3: Cross multiply
    1,131.50x = 1,561.66 × 665.66
  4. Step 4: Simplify right side
    1,131.50x = 1,039,534.60
  5. Step 5: Solve for x
    x = 1,039,534.60/1,131.50
  6. Step 6: Final answer
    x = 918.72

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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.