Home / 208.78-312.90-86.88

Finding the Fourth Proportional to 208.78, 312.90 and 86.88

Calculator

Solution

The fourth proportional to 208.78, 312.90 and 86.88 is: 130.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.78 : 312.90 = 86.88 : x
  2. Step 2: Convert to fraction form
    208.78/312.90 = 86.88/x
  3. Step 3: Cross multiply
    208.78x = 312.90 × 86.88
  4. Step 4: Simplify right side
    208.78x = 27,183.19
  5. Step 5: Solve for x
    x = 27,183.19/208.78
  6. Step 6: Final answer
    x = 130.20

Related Problems

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.