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Finding the Fourth Proportional to 420.18, 626.57 and 390.96

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Solution

The fourth proportional to 420.18, 626.57 and 390.96 is: 582.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.18 : 626.57 = 390.96 : x
  2. Step 2: Convert to fraction form
    420.18/626.57 = 390.96/x
  3. Step 3: Cross multiply
    420.18x = 626.57 × 390.96
  4. Step 4: Simplify right side
    420.18x = 244,961.85
  5. Step 5: Solve for x
    x = 244,961.85/420.18
  6. Step 6: Final answer
    x = 582.99

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.