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Finding the Fourth Proportional to 665.80, 918.66 and 561.28

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Solution

The fourth proportional to 665.80, 918.66 and 561.28 is: 774.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.80 : 918.66 = 561.28 : x
  2. Step 2: Convert to fraction form
    665.80/918.66 = 561.28/x
  3. Step 3: Cross multiply
    665.80x = 918.66 × 561.28
  4. Step 4: Simplify right side
    665.80x = 515,625.48
  5. Step 5: Solve for x
    x = 515,625.48/665.80
  6. Step 6: Final answer
    x = 774.45

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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.