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Finding the Fourth Proportional to 830.58, 1,139.38 and 780.90

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Solution

The fourth proportional to 830.58, 1,139.38 and 780.90 is: 1,071.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    830.58 : 1,139.38 = 780.90 : x
  2. Step 2: Convert to fraction form
    830.58/1,139.38 = 780.90/x
  3. Step 3: Cross multiply
    830.58x = 1,139.38 × 780.90
  4. Step 4: Simplify right side
    830.58x = 889,741.84
  5. Step 5: Solve for x
    x = 889,741.84/830.58
  6. Step 6: Final answer
    x = 1,071.23

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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.