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Finding the Fourth Proportional to 981.21, 1,354.13 and 561.70

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Solution

The fourth proportional to 981.21, 1,354.13 and 561.70 is: 775.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.21 : 1,354.13 = 561.70 : x
  2. Step 2: Convert to fraction form
    981.21/1,354.13 = 561.70/x
  3. Step 3: Cross multiply
    981.21x = 1,354.13 × 561.70
  4. Step 4: Simplify right side
    981.21x = 760,615.16
  5. Step 5: Solve for x
    x = 760,615.16/981.21
  6. Step 6: Final answer
    x = 775.18

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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.