Answer:
31.5/15 = 2.1
2.1 x 18 =37.8
Check by Soh Cah Toa
1) Tan-(15/18)=40* to 1d.p for angle ACB
Tan-(18/15)=50* to 1d.p for angle ABC
40 + 50=90
90+90 (in the right angled triangle) =180*
Angle in triangle add to 180
Let's check for the big triangle:
Opposite angles are equal. So, DCE is 40.
DE is opposite, x is adjacent.
Tan(40) = o/a
=31.5/x
Multiply by x both side
Tan(40) multiply by x = 31.5
Divide by Tan(40) both side and get x on its own.
x=31.5/Tan(40)
= 37.54023817.
So, x = 37.5 to 1 d.p
Pythag to fin hypotenuse of both triangle and divided by each other to see if it matches decimal multiplier at the start of my solution.
49/23=2.1 (all values to 1d.p)
Also, 37.5/18 = 2.1 to 1 d.p