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Finding the Fourth Proportional to 885, 1,217.70 and 812.10

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Solution

The fourth proportional to 885, 1,217.70 and 812.10 is: 1,117.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    885 : 1,217.70 = 812.10 : x
  2. Step 2: Convert to fraction form
    885/1,217.70 = 812.10/x
  3. Step 3: Cross multiply
    885x = 1,217.70 × 812.10
  4. Step 4: Simplify right side
    885x = 988,894.17
  5. Step 5: Solve for x
    x = 988,894.17/885
  6. Step 6: Final answer
    x = 1,117.39

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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.