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Finding the Fourth Proportional to 1,851.80, 2,780.90 and 987.80

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Solution

The fourth proportional to 1,851.80, 2,780.90 and 987.80 is: 1,483.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,851.80 : 2,780.90 = 987.80 : x
  2. Step 2: Convert to fraction form
    1,851.80/2,780.90 = 987.80/x
  3. Step 3: Cross multiply
    1,851.80x = 2,780.90 × 987.80
  4. Step 4: Simplify right side
    1,851.80x = 2,746,973.02
  5. Step 5: Solve for x
    x = 2,746,973.02/1,851.80
  6. Step 6: Final answer
    x = 1,483.41

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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.