43.0k views
4 votes
If the geometric mean of a and 28 is 16 sqrt 7 find a

User Hlh
by
4.4k points

2 Answers

4 votes

Answer:

a = 64

Explanation:

The geometric mean of 2 numbers a and b is
√(ab) , then


√(28a) = 16
√(7) ( square both sides )

28a = (16
√(7) )² = 1792 ( divide both sides by 28 )

a = 64

User Misha M
by
4.2k points
3 votes

Answer:

a = 64

Explanation:

The geometric mean for two numbers is given by :

GM = sqrt(ab)

16 sqrt(7) = sqrt(a*28)

Square each side

(16 sqrt(7))^2 = (sqrt(a*28))^2

256*7 = 28a

1792 = 28a

Divide each side by 28

1792/28 = 28a/28

64 = a

User Bert Wagner
by
4.6k points