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Finding the Fourth Proportional to 688.19, 949.61 and 393.40

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Solution

The fourth proportional to 688.19, 949.61 and 393.40 is: 542.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.19 : 949.61 = 393.40 : x
  2. Step 2: Convert to fraction form
    688.19/949.61 = 393.40/x
  3. Step 3: Cross multiply
    688.19x = 949.61 × 393.40
  4. Step 4: Simplify right side
    688.19x = 373,569.86
  5. Step 5: Solve for x
    x = 373,569.86/688.19
  6. Step 6: Final answer
    x = 542.83

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Half scale
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Double 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.