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Finding the Fourth Proportional to 831.42, 1,139.16 and 821.18

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Solution

The fourth proportional to 831.42, 1,139.16 and 821.18 is: 1,125.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.42 : 1,139.16 = 821.18 : x
  2. Step 2: Convert to fraction form
    831.42/1,139.16 = 821.18/x
  3. Step 3: Cross multiply
    831.42x = 1,139.16 × 821.18
  4. Step 4: Simplify right side
    831.42x = 935,455.41
  5. Step 5: Solve for x
    x = 935,455.41/831.42
  6. Step 6: Final answer
    x = 1,125.13

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.