Home / 1,221.76-1,686-669.76

Finding the Fourth Proportional to 1,221.76, 1,686 and 669.76

Calculator

Solution

The fourth proportional to 1,221.76, 1,686 and 669.76 is: 924.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.76 : 1,686 = 669.76 : x
  2. Step 2: Convert to fraction form
    1,221.76/1,686 = 669.76/x
  3. Step 3: Cross multiply
    1,221.76x = 1,686 × 669.76
  4. Step 4: Simplify right side
    1,221.76x = 1,129,215.36
  5. Step 5: Solve for x
    x = 1,129,215.36/1,221.76
  6. Step 6: Final answer
    x = 924.25

Related Problems

Find fourth proportional to 610.88, 843 and 334.88
Half scale
Find fourth proportional to 2,443.52, 3,372 and 1,339.52
Double scale
Find fourth proportional to 1,222.76, 1,687.38 and 670.76
Similar ratio
Find fourth proportional to 1,832.64, 2,529 and 1,004.64
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.