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Finding the Fourth Proportional to 684.92, 945.17 and 390.19

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Solution

The fourth proportional to 684.92, 945.17 and 390.19 is: 538.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.92 : 945.17 = 390.19 : x
  2. Step 2: Convert to fraction form
    684.92/945.17 = 390.19/x
  3. Step 3: Cross multiply
    684.92x = 945.17 × 390.19
  4. Step 4: Simplify right side
    684.92x = 368,795.88
  5. Step 5: Solve for x
    x = 368,795.88/684.92
  6. Step 6: Final answer
    x = 538.45

Related Problems

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Half scale
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Double scale
Find fourth proportional to 685.92, 946.55 and 391.19
Similar ratio
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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.