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Finding the Fourth Proportional to 938.66, 1,295.19 and 640.15

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Solution

The fourth proportional to 938.66, 1,295.19 and 640.15 is: 883.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.66 : 1,295.19 = 640.15 : x
  2. Step 2: Convert to fraction form
    938.66/1,295.19 = 640.15/x
  3. Step 3: Cross multiply
    938.66x = 1,295.19 × 640.15
  4. Step 4: Simplify right side
    938.66x = 829,119.93
  5. Step 5: Solve for x
    x = 829,119.93/938.66
  6. Step 6: Final answer
    x = 883.30

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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.