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Finding the Fourth Proportional to 1,120.70, 1,681.19 and 390.17

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Solution

The fourth proportional to 1,120.70, 1,681.19 and 390.17 is: 585.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,120.70 : 1,681.19 = 390.17 : x
  2. Step 2: Convert to fraction form
    1,120.70/1,681.19 = 390.17/x
  3. Step 3: Cross multiply
    1,120.70x = 1,681.19 × 390.17
  4. Step 4: Simplify right side
    1,120.70x = 655,955.08
  5. Step 5: Solve for x
    x = 655,955.08/1,120.70
  6. Step 6: Final answer
    x = 585.31

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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.