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Finding the Fourth Proportional to 981.50, 1,354.38 and 561.78

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Solution

The fourth proportional to 981.50, 1,354.38 and 561.78 is: 775.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.50 : 1,354.38 = 561.78 : x
  2. Step 2: Convert to fraction form
    981.50/1,354.38 = 561.78/x
  3. Step 3: Cross multiply
    981.50x = 1,354.38 × 561.78
  4. Step 4: Simplify right side
    981.50x = 760,863.60
  5. Step 5: Solve for x
    x = 760,863.60/981.50
  6. Step 6: Final answer
    x = 775.20

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1.5x scale

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.