Home / 63.78-95.61-21

Finding the Fourth Proportional to 63.78, 95.61 and 21

Calculator

Solution

The fourth proportional to 63.78, 95.61 and 21 is: 31.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    63.78 : 95.61 = 21 : x
  2. Step 2: Convert to fraction form
    63.78/95.61 = 21/x
  3. Step 3: Cross multiply
    63.78x = 95.61 × 21
  4. Step 4: Simplify right side
    63.78x = 2,007.81
  5. Step 5: Solve for x
    x = 2,007.81/63.78
  6. Step 6: Final answer
    x = 31.48

Related Problems

Find fourth proportional to 31.89, 47.81 and 10.50
Half scale
Find fourth proportional to 127.56, 191.22 and 42
Double scale
Find fourth proportional to 64.78, 97.11 and 22
Similar ratio
Find fourth proportional to 95.67, 143.42 and 31.50
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.