Home / 123.45-170.40-76.86

Finding the Fourth Proportional to 123.45, 170.40 and 76.86

Calculator

Solution

The fourth proportional to 123.45, 170.40 and 76.86 is: 106.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.45 : 170.40 = 76.86 : x
  2. Step 2: Convert to fraction form
    123.45/170.40 = 76.86/x
  3. Step 3: Cross multiply
    123.45x = 170.40 × 76.86
  4. Step 4: Simplify right side
    123.45x = 13,096.93
  5. Step 5: Solve for x
    x = 13,096.93/123.45
  6. Step 6: Final answer
    x = 106.09

Related Problems

Find fourth proportional to 61.72, 85.20 and 38.43
Half scale
Find fourth proportional to 246.89, 340.81 and 153.72
Double scale
Find fourth proportional to 124.45, 171.78 and 77.86
Similar ratio
Find fourth proportional to 185.17, 255.61 and 115.29
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.