Pls show all your working out brainliest

Area of a triangle = height x base ÷ 2

When ever you have an isosceles triangle, remember that you can split it in half to form two right angled triangles - which allow you to use Pythagoras' Theorem.

So we split 10cm in half to get 5cm.

We can then use 13cm and 5cm to work out the height:

Height = √(13²  - 5²)      (Note: you subtract because you are using the    

           = √144              (hypotenuse)

           =  12

Now to get the area, we just multiply the base (which is 10) by the height (which is 12) and divide by 2:

Area = 12 x 10 ÷ 2

        = 6 x 10               (note: 12 ÷ 2 = 6 )

        = 60 cm²

60 cm²

cut 138 centimeters off

step-by-step explanation:

250-112 = 138