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Finding the Fourth Proportional to 811.40, 1,119.92 and 678.47

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Solution

The fourth proportional to 811.40, 1,119.92 and 678.47 is: 936.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.40 : 1,119.92 = 678.47 : x
  2. Step 2: Convert to fraction form
    811.40/1,119.92 = 678.47/x
  3. Step 3: Cross multiply
    811.40x = 1,119.92 × 678.47
  4. Step 4: Simplify right side
    811.40x = 759,831.53
  5. Step 5: Solve for x
    x = 759,831.53/811.40
  6. Step 6: Final answer
    x = 936.44

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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.