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Finding the Fourth Proportional to 1,030.80, 1,420.50 and 719.76

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Solution

The fourth proportional to 1,030.80, 1,420.50 and 719.76 is: 991.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,030.80 : 1,420.50 = 719.76 : x
  2. Step 2: Convert to fraction form
    1,030.80/1,420.50 = 719.76/x
  3. Step 3: Cross multiply
    1,030.80x = 1,420.50 × 719.76
  4. Step 4: Simplify right side
    1,030.80x = 1,022,419.08
  5. Step 5: Solve for x
    x = 1,022,419.08/1,030.80
  6. Step 6: Final answer
    x = 991.87

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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.