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Finding the Fourth Proportional to 685.03, 945.21 and 390.22

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Solution

The fourth proportional to 685.03, 945.21 and 390.22 is: 538.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.03 : 945.21 = 390.22 : x
  2. Step 2: Convert to fraction form
    685.03/945.21 = 390.22/x
  3. Step 3: Cross multiply
    685.03x = 945.21 × 390.22
  4. Step 4: Simplify right side
    685.03x = 368,839.85
  5. Step 5: Solve for x
    x = 368,839.85/685.03
  6. Step 6: Final answer
    x = 538.43

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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.