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Finding the Fourth Proportional to 685.88, 946.30 and 420.18

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Solution

The fourth proportional to 685.88, 946.30 and 420.18 is: 579.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.88 : 946.30 = 420.18 : x
  2. Step 2: Convert to fraction form
    685.88/946.30 = 420.18/x
  3. Step 3: Cross multiply
    685.88x = 946.30 × 420.18
  4. Step 4: Simplify right side
    685.88x = 397,616.66
  5. Step 5: Solve for x
    x = 397,616.66/685.88
  6. Step 6: Final answer
    x = 579.72

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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.