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Finding the Fourth Proportional to 661.40, 912.65 and 381.60

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Solution

The fourth proportional to 661.40, 912.65 and 381.60 is: 526.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.40 : 912.65 = 381.60 : x
  2. Step 2: Convert to fraction form
    661.40/912.65 = 381.60/x
  3. Step 3: Cross multiply
    661.40x = 912.65 × 381.60
  4. Step 4: Simplify right side
    661.40x = 348,267.24
  5. Step 5: Solve for x
    x = 348,267.24/661.40
  6. Step 6: Final answer
    x = 526.56

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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.