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Finding the Fourth Proportional to 1,387.79, 2,080.87 and 521.63

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Solution

The fourth proportional to 1,387.79, 2,080.87 and 521.63 is: 782.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.79 : 2,080.87 = 521.63 : x
  2. Step 2: Convert to fraction form
    1,387.79/2,080.87 = 521.63/x
  3. Step 3: Cross multiply
    1,387.79x = 2,080.87 × 521.63
  4. Step 4: Simplify right side
    1,387.79x = 1,085,432.51
  5. Step 5: Solve for x
    x = 1,085,432.51/1,387.79
  6. Step 6: Final answer
    x = 782.13

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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.