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Finding the Fourth Proportional to 948.80, 1,421.40 and 811.10

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Solution

The fourth proportional to 948.80, 1,421.40 and 811.10 is: 1,215.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    948.80 : 1,421.40 = 811.10 : x
  2. Step 2: Convert to fraction form
    948.80/1,421.40 = 811.10/x
  3. Step 3: Cross multiply
    948.80x = 1,421.40 × 811.10
  4. Step 4: Simplify right side
    948.80x = 1,152,897.54
  5. Step 5: Solve for x
    x = 1,152,897.54/948.80
  6. Step 6: Final answer
    x = 1,215.11

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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.