Find x. A. 21√2 B. 7 C. 21√3 over 2 D. 21√2 over 2

D

Step-by-step explanation:

Using sine ratio in left right angled triangle to find the altitude a of the large triangle which is common to both right triangles and the exact value

sin60° = , then

sin60° = = = ( cross- multiply )

2a = 21 ( divide both sides by 2 )

a =

Using the cosine ratio in the right side triangle and the exact value

cos45° = , then

cos45° = = = ( cross- multiply )

x = a = × = → D

the answer is b

right

step-by-step explanation: