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Finding the Fourth Proportional to 661.80, 912.44 and 428.80

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Solution

The fourth proportional to 661.80, 912.44 and 428.80 is: 591.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.80 : 912.44 = 428.80 : x
  2. Step 2: Convert to fraction form
    661.80/912.44 = 428.80/x
  3. Step 3: Cross multiply
    661.80x = 912.44 × 428.80
  4. Step 4: Simplify right side
    661.80x = 391,254.27
  5. Step 5: Solve for x
    x = 391,254.27/661.80
  6. Step 6: Final answer
    x = 591.20

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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.