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Finding the Fourth Proportional to 374.40, 561.60 and 319.20

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Solution

The fourth proportional to 374.40, 561.60 and 319.20 is: 478.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    374.40 : 561.60 = 319.20 : x
  2. Step 2: Convert to fraction form
    374.40/561.60 = 319.20/x
  3. Step 3: Cross multiply
    374.40x = 561.60 × 319.20
  4. Step 4: Simplify right side
    374.40x = 179,262.72
  5. Step 5: Solve for x
    x = 179,262.72/374.40
  6. Step 6: Final answer
    x = 478.80

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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.