Home / 156.31-215.71-87.31

Finding the Fourth Proportional to 156.31, 215.71 and 87.31

Calculator

Solution

The fourth proportional to 156.31, 215.71 and 87.31 is: 120.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.31 : 215.71 = 87.31 : x
  2. Step 2: Convert to fraction form
    156.31/215.71 = 87.31/x
  3. Step 3: Cross multiply
    156.31x = 215.71 × 87.31
  4. Step 4: Simplify right side
    156.31x = 18,834.29
  5. Step 5: Solve for x
    x = 18,834.29/156.31
  6. Step 6: Final answer
    x = 120.49

Related Problems

Find fourth proportional to 78.16, 107.86 and 43.66
Half scale
Find fourth proportional to 312.63, 431.42 and 174.63
Double scale
Find fourth proportional to 157.31, 217.09 and 88.31
Similar ratio
Find fourth proportional to 234.47, 323.57 and 130.97
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.