Home / 86.00-129-31.89

Finding the Fourth Proportional to 86.00, 129 and 31.89

Calculator

Solution

The fourth proportional to 86.00, 129 and 31.89 is: 47.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.00 : 129 = 31.89 : x
  2. Step 2: Convert to fraction form
    86.00/129 = 31.89/x
  3. Step 3: Cross multiply
    86.00x = 129 × 31.89
  4. Step 4: Simplify right side
    86.00x = 4,113.81
  5. Step 5: Solve for x
    x = 4,113.81/86.00
  6. Step 6: Final answer
    x = 47.84

Related Problems

Find fourth proportional to 43.00, 64.50 and 15.95
Half scale
Find fourth proportional to 171.99, 258 and 63.78
Double scale
Find fourth proportional to 87, 130.50 and 32.89
Similar ratio
Find fourth proportional to 128.99, 193.50 and 47.84
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.