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Finding the Fourth Proportional to 1,390.90, 2,088.51 and 742.90

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Solution

The fourth proportional to 1,390.90, 2,088.51 and 742.90 is: 1,115.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.90 : 2,088.51 = 742.90 : x
  2. Step 2: Convert to fraction form
    1,390.90/2,088.51 = 742.90/x
  3. Step 3: Cross multiply
    1,390.90x = 2,088.51 × 742.90
  4. Step 4: Simplify right side
    1,390.90x = 1,551,554.08
  5. Step 5: Solve for x
    x = 1,551,554.08/1,390.90
  6. Step 6: Final answer
    x = 1,115.50

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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.