Home / 11.50-15.87-9.78

Finding the Fourth Proportional to 11.50, 15.87 and 9.78

Calculator

Solution

The fourth proportional to 11.50, 15.87 and 9.78 is: 13.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.50 : 15.87 = 9.78 : x
  2. Step 2: Convert to fraction form
    11.50/15.87 = 9.78/x
  3. Step 3: Cross multiply
    11.50x = 15.87 × 9.78
  4. Step 4: Simplify right side
    11.50x = 155.27
  5. Step 5: Solve for x
    x = 155.27/11.50
  6. Step 6: Final answer
    x = 13.50

Related Problems

Find fourth proportional to 5.75, 7.94 and 4.89
Half scale
Find fourth proportional to 23.01, 31.74 and 19.57
Double scale
Find fourth proportional to 12.50, 17.25 and 10.78
Similar ratio
Find fourth proportional to 17.26, 23.81 and 14.67
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.