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Finding the Fourth Proportional to 715.96, 988.16 and 421.20

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Solution

The fourth proportional to 715.96, 988.16 and 421.20 is: 581.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.96 : 988.16 = 421.20 : x
  2. Step 2: Convert to fraction form
    715.96/988.16 = 421.20/x
  3. Step 3: Cross multiply
    715.96x = 988.16 × 421.20
  4. Step 4: Simplify right side
    715.96x = 416,212.99
  5. Step 5: Solve for x
    x = 416,212.99/715.96
  6. Step 6: Final answer
    x = 581.34

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Half scale
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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.