Question

Need help step by step find the missing side thanks

Answer 1

Answer:

$\sqrt{87}$

Step-by-step explanation:

Let AB=16,BC=5,CD=x,DA=18

BC and DA are perpendicular to CD

Draw a line from B parallel to CD intersecting DA at E.

As BCDE is a rectangle(all angles of quadrilateral=90)

Therefore BE=CD=x and ED=BC=5(opposite sides are equal in a rectangle)

⇒AD=AE+ED

18=AE+5

AE=13

⇒ By Pythogores theorem in right angled triangle ABE

$AB^{2} =BE^{2} +EA^{2}$

$16^{2} =x^{2} +13^{2}$

$x^{2} =256-169$

x=$\sqrt{87}$