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Finding the Fourth Proportional to 831.40, 1,245.30 and 740.20

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Solution

The fourth proportional to 831.40, 1,245.30 and 740.20 is: 1,108.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.40 : 1,245.30 = 740.20 : x
  2. Step 2: Convert to fraction form
    831.40/1,245.30 = 740.20/x
  3. Step 3: Cross multiply
    831.40x = 1,245.30 × 740.20
  4. Step 4: Simplify right side
    831.40x = 921,771.06
  5. Step 5: Solve for x
    x = 921,771.06/831.40
  6. Step 6: Final answer
    x = 1,108.70

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.