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Finding the Fourth Proportional to 648.48, 972.24 and 420

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Solution

The fourth proportional to 648.48, 972.24 and 420 is: 629.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    648.48 : 972.24 = 420 : x
  2. Step 2: Convert to fraction form
    648.48/972.24 = 420/x
  3. Step 3: Cross multiply
    648.48x = 972.24 × 420
  4. Step 4: Simplify right side
    648.48x = 408,340.80
  5. Step 5: Solve for x
    x = 408,340.80/648.48
  6. Step 6: Final answer
    x = 629.69

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.