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Finding the Fourth Proportional to 803.40, 1,205.10 and 621.15

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Solution

The fourth proportional to 803.40, 1,205.10 and 621.15 is: 931.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    803.40 : 1,205.10 = 621.15 : x
  2. Step 2: Convert to fraction form
    803.40/1,205.10 = 621.15/x
  3. Step 3: Cross multiply
    803.40x = 1,205.10 × 621.15
  4. Step 4: Simplify right side
    803.40x = 748,547.87
  5. Step 5: Solve for x
    x = 748,547.87/803.40
  6. Step 6: Final answer
    x = 931.73

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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.