Home / 861.72-1,186.98-728.80

Finding the Fourth Proportional to 861.72, 1,186.98 and 728.80

Calculator

Solution

The fourth proportional to 861.72, 1,186.98 and 728.80 is: 1,003.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.72 : 1,186.98 = 728.80 : x
  2. Step 2: Convert to fraction form
    861.72/1,186.98 = 728.80/x
  3. Step 3: Cross multiply
    861.72x = 1,186.98 × 728.80
  4. Step 4: Simplify right side
    861.72x = 865,071.02
  5. Step 5: Solve for x
    x = 865,071.02/861.72
  6. Step 6: Final answer
    x = 1,003.89

Related Problems

Find fourth proportional to 430.86, 593.49 and 364.40
Half scale
Find fourth proportional to 1,723.44, 2,373.96 and 1,457.60
Double scale
Find fourth proportional to 862.72, 1,188.36 and 729.80
Similar ratio
Find fourth proportional to 1,292.58, 1,780.47 and 1,093.20
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.