http://www.ck12.org Chapter 1. Basics of Geometry
3.
4.
5.
- Can you draw a triangle with a right angle and an obtuse angle? Why or why not?
- In an isosceles triangle, can the angles opposite the congruent sides be obtuse?
8.ConstructionConstruct an equilateral triangle with sides of 3 cm. Start by drawing a horizontal segment of 3
cm and measure this side with your compass from both endpoints. - What must be true about the angles of your equilateral triangle from #8?
For 10-14, determine if the statement is ALWAYS true, SOMETIMES true, or NEVER true.
- Obtuse triangles are isosceles.
- A right triangle is acute.
- An equilateral triangle is equiangular.
- An isosceles triangle is equilaterals.
- Equiangular triangles are scalene.
In geometry it is important to know the difference between a sketch, a drawing and a construction. A sketch is
usually drawn free-hand and marked with the appropriate congruence markings or labeled with measurement. It
may or may not be drawn to scale. A drawing is made using a ruler, protractor or compass and should be made to
scale. A construction is made using only a compass and ruler and should be made to scale.
For 15-16, construct the indicated figures.
- Construct a right triangle with side lengths 3 cm, 4 cm and 5 cm.
- Construct a 60◦angle. (Hint: Think about an equilateral triangle.)