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Finding the Fourth Proportional to 665.40, 918.64 and 488.21

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Solution

The fourth proportional to 665.40, 918.64 and 488.21 is: 674.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.40 : 918.64 = 488.21 : x
  2. Step 2: Convert to fraction form
    665.40/918.64 = 488.21/x
  3. Step 3: Cross multiply
    665.40x = 918.64 × 488.21
  4. Step 4: Simplify right side
    665.40x = 448,489.23
  5. Step 5: Solve for x
    x = 448,489.23/665.40
  6. Step 6: Final answer
    x = 674.01

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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.