Question

Find the value of x.

Answer 1

Answer:

$\huge\boxed{x=\sqrt{70}}$

Step-by-step explanation:

ΔABC and ΔADB are similar (AAA).

Therefore the corresponging sides are in proportion:

$\dfrac{AB}{AD}=\dfrac{AC}{AB}$

Substitute:

$AB=x\\AC=7+3=10\\AD=7$

$\dfrac{x}{7}=\dfrac{10}{x}$       cross multiply

$(x)(x)=(7)(10)\\\\x^2=70\to x=\sqrt{70}$