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Finding the Fourth Proportional to 911.85, 1,257.28 and 712.18

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Solution

The fourth proportional to 911.85, 1,257.28 and 712.18 is: 981.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.85 : 1,257.28 = 712.18 : x
  2. Step 2: Convert to fraction form
    911.85/1,257.28 = 712.18/x
  3. Step 3: Cross multiply
    911.85x = 1,257.28 × 712.18
  4. Step 4: Simplify right side
    911.85x = 895,409.67
  5. Step 5: Solve for x
    x = 895,409.67/911.85
  6. Step 6: Final answer
    x = 981.97

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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.