Area of a triangle = height x base ÷ 2When 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 _____________________________________Answer:60 cm²