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Finding the Fourth Proportional to 665.38, 918.30 and 385.66

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Solution

The fourth proportional to 665.38, 918.30 and 385.66 is: 532.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.38 : 918.30 = 385.66 : x
  2. Step 2: Convert to fraction form
    665.38/918.30 = 385.66/x
  3. Step 3: Cross multiply
    665.38x = 918.30 × 385.66
  4. Step 4: Simplify right side
    665.38x = 354,151.58
  5. Step 5: Solve for x
    x = 354,151.58/665.38
  6. Step 6: Final answer
    x = 532.25

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1.5x scale

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.