9. Draw a square which sides are 6 cm. Inside the square draw an equilateral triangle which side is 3 cm. Streak the area outside the triangle and find the area. Measure all the other sides.

10. Draw a rectangle which sides are 3 cm and 6 cm. On the shorter side of the rectangle draw a semicircle and on the other side draw an isosceles triangle which side is 2.5 cm. Do the necessary measurements and find the area of the object.

11. The base of a triangle is 64 cm and the altitude to it is 20% shorter. Find the area of the triangle.

12. Draw triangle KLM which side KL=5 cm and which adjacent angles are 40° and 60°. Draw three altitudes to the triangle. Find the area by those three altitudes. Compare the results.