Home / 1,420.10-2,127.30-687.45

Finding the Fourth Proportional to 1,420.10, 2,127.30 and 687.45

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Solution

The fourth proportional to 1,420.10, 2,127.30 and 687.45 is: 1,029.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.10 : 2,127.30 = 687.45 : x
  2. Step 2: Convert to fraction form
    1,420.10/2,127.30 = 687.45/x
  3. Step 3: Cross multiply
    1,420.10x = 2,127.30 × 687.45
  4. Step 4: Simplify right side
    1,420.10x = 1,462,412.39
  5. Step 5: Solve for x
    x = 1,462,412.39/1,420.10
  6. Step 6: Final answer
    x = 1,029.80

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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.