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Finding the Fourth Proportional to 684.74, 945 and 390.11

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Solution

The fourth proportional to 684.74, 945 and 390.11 is: 538.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.74 : 945 = 390.11 : x
  2. Step 2: Convert to fraction form
    684.74/945 = 390.11/x
  3. Step 3: Cross multiply
    684.74x = 945 × 390.11
  4. Step 4: Simplify right side
    684.74x = 368,649.23
  5. Step 5: Solve for x
    x = 368,649.23/684.74
  6. Step 6: Final answer
    x = 538.38

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Double scale
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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.