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Finding the Fourth Proportional to 665.88, 918.91 and 389.88

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Solution

The fourth proportional to 665.88, 918.91 and 389.88 is: 538.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.88 : 918.91 = 389.88 : x
  2. Step 2: Convert to fraction form
    665.88/918.91 = 389.88/x
  3. Step 3: Cross multiply
    665.88x = 918.91 × 389.88
  4. Step 4: Simplify right side
    665.88x = 358,264.63
  5. Step 5: Solve for x
    x = 358,264.63/665.88
  6. Step 6: Final answer
    x = 538.03

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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.