Question

If numbers 9 : z : : z : 81 are in proportion then the value of z is

Answer 1

Answer:

b = 7

proportion is = 9 : 27 : : 27 : 81

Step-by-step explanation:

9 : z : : z : 81

a : b : : b : c

Here we will formula of mean proportion

${b}^{2} = ac = 9 \times 81 = 729 \\ {b}^{2} = {27}^{2} \\ b = 27$