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Finding the Fourth Proportional to 515.60, 710.72 and 390.76

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Solution

The fourth proportional to 515.60, 710.72 and 390.76 is: 538.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.60 : 710.72 = 390.76 : x
  2. Step 2: Convert to fraction form
    515.60/710.72 = 390.76/x
  3. Step 3: Cross multiply
    515.60x = 710.72 × 390.76
  4. Step 4: Simplify right side
    515.60x = 277,720.95
  5. Step 5: Solve for x
    x = 277,720.95/515.60
  6. Step 6: Final answer
    x = 538.64

Related Problems

Find fourth proportional to 257.80, 355.36 and 195.38
Half scale
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Double scale
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Similar ratio
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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.