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Finding the Fourth Proportional to 1,985.60, 2,977.56 and 687.20

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Solution

The fourth proportional to 1,985.60, 2,977.56 and 687.20 is: 1,030.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,985.60 : 2,977.56 = 687.20 : x
  2. Step 2: Convert to fraction form
    1,985.60/2,977.56 = 687.20/x
  3. Step 3: Cross multiply
    1,985.60x = 2,977.56 × 687.20
  4. Step 4: Simplify right side
    1,985.60x = 2,046,179.23
  5. Step 5: Solve for x
    x = 2,046,179.23/1,985.60
  6. Step 6: Final answer
    x = 1,030.51

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1.5x scale

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.