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Finding the Fourth Proportional to 1,130.40, 1,690.20 and 838.80

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Solution

The fourth proportional to 1,130.40, 1,690.20 and 838.80 is: 1,254.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,130.40 : 1,690.20 = 838.80 : x
  2. Step 2: Convert to fraction form
    1,130.40/1,690.20 = 838.80/x
  3. Step 3: Cross multiply
    1,130.40x = 1,690.20 × 838.80
  4. Step 4: Simplify right side
    1,130.40x = 1,417,739.76
  5. Step 5: Solve for x
    x = 1,417,739.76/1,130.40
  6. Step 6: Final answer
    x = 1,254.19

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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.