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Finding the Fourth Proportional to 1,238.38, 1,708.96 and 686.38

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Solution

The fourth proportional to 1,238.38, 1,708.96 and 686.38 is: 947.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.38 : 1,708.96 = 686.38 : x
  2. Step 2: Convert to fraction form
    1,238.38/1,708.96 = 686.38/x
  3. Step 3: Cross multiply
    1,238.38x = 1,708.96 × 686.38
  4. Step 4: Simplify right side
    1,238.38x = 1,172,987.42
  5. Step 5: Solve for x
    x = 1,172,987.42/1,238.38
  6. Step 6: Final answer
    x = 947.20

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Half scale
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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.