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Finding the Fourth Proportional to 831.42, 1,146.42 and 781.20

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Solution

The fourth proportional to 831.42, 1,146.42 and 781.20 is: 1,077.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.42 : 1,146.42 = 781.20 : x
  2. Step 2: Convert to fraction form
    831.42/1,146.42 = 781.20/x
  3. Step 3: Cross multiply
    831.42x = 1,146.42 × 781.20
  4. Step 4: Simplify right side
    831.42x = 895,583.30
  5. Step 5: Solve for x
    x = 895,583.30/831.42
  6. Step 6: Final answer
    x = 1,077.17

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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.