Calculate the length of AC to one decimal place in the trapezium below.

First we will split trapezium on two geometric figure.

One is rectangle and the second is right triangle.

When we subtract 11-4=7cm we get one cathetus of the right triangle a=7cm also we know hypotenuse which is c=16cm.

We will use Pythagorean theorem to find the second cathetus b

b=√16∧2-7∧2 = √256-49 = √207 ≈ 14.39cm = DC = >

AC = √ (DC) ∧2 + (AD) ∧2 = √14.39∧2+11∧2 = √207+121 = √328 = 18.1cm

AC=18.1cm

Good luck!