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Finding the Fourth Proportional to 661.57, 913.35 and 399.67

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Solution

The fourth proportional to 661.57, 913.35 and 399.67 is: 551.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.57 : 913.35 = 399.67 : x
  2. Step 2: Convert to fraction form
    661.57/913.35 = 399.67/x
  3. Step 3: Cross multiply
    661.57x = 913.35 × 399.67
  4. Step 4: Simplify right side
    661.57x = 365,038.59
  5. Step 5: Solve for x
    x = 365,038.59/661.57
  6. Step 6: Final answer
    x = 551.78

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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.