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Finding the Fourth Proportional to 684.90, 945.12 and 390.18

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Solution

The fourth proportional to 684.90, 945.12 and 390.18 is: 538.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.90 : 945.12 = 390.18 : x
  2. Step 2: Convert to fraction form
    684.90/945.12 = 390.18/x
  3. Step 3: Cross multiply
    684.90x = 945.12 × 390.18
  4. Step 4: Simplify right side
    684.90x = 368,766.92
  5. Step 5: Solve for x
    x = 368,766.92/684.90
  6. Step 6: Final answer
    x = 538.42

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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.