Respuesta :

Answer: X = 7√2

Step-by-step explanation:

Let first Consider triangle BDC,

Cos C = adjacent/ hypothenus

Cos C = 7 / x ...... (1)

Also, let consider triangle ABC

Cos C = adjacent / hypothenus

Cos C = x / 14 ....... (2)

Since angle C is the same, equate equation 1 to 2

7/ x = x / 14

Cross multiply

X^2 = 98

Make x the subject of formula

X = sqrt (98)

X = sqrt ( 49 × 2 )

X = sqrt (49) × sqrt (2)

X = 7 sqrt(2)

X = 7√2