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Finding the Fourth Proportional to 1,131.25, 1,561.40 and 665.77

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Solution

The fourth proportional to 1,131.25, 1,561.40 and 665.77 is: 918.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,131.25 : 1,561.40 = 665.77 : x
  2. Step 2: Convert to fraction form
    1,131.25/1,561.40 = 665.77/x
  3. Step 3: Cross multiply
    1,131.25x = 1,561.40 × 665.77
  4. Step 4: Simplify right side
    1,131.25x = 1,039,533.28
  5. Step 5: Solve for x
    x = 1,039,533.28/1,131.25
  6. Step 6: Final answer
    x = 918.92

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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.