# Grade 8

### Geometry worksheet answer key + Algebra worksheet

**Before you can add or subtract fractions, the fractions need to have a common denominator (in other words the denominators must be the same). If the denominators are not the same, you can use the Least Common Denominator to make them the same.**

*To practice with adding and subtracting Algebraic Fractions** click here*

*The answer key will be released by Thursday 21st of march within this post.*

**Geometry worksheet answer key: See how well you did!*** ***click here**** **

**Algebra worksheet answer key: See how well you did!*** ***click here**** **

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### Tips for working with Congruent Triangles + Practice Questions

There are 4 combination methods (**SSS–SAS–ASA–AAS**) that allow us to show triangles to be congruent.

###### (*click on the image to enlarge*)

But how do we decide which method we should be using?

**Let’s look at some important tips:**

**1-** Mark any given information on the diagram.

**2-** Mark any other congruent parts you notice. like:

* ( Vertical angles, Shared side, Alternate angles, 3rd angles , …)*

*(click on the image to enlarge)*

**3-** Stay open-minded. There may be more than one way to solve a problem.

*Remember that proving triangles congruent is like solving a puzzle. *

* Look carefully at the “puzzle” and use all of your geometrical strategies to arrive at an answer.*

*Let’s see how well you learned the lesson! click here*

*The answer key will be available by Tuesday 19th of march along with a new algebra worksheet*

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### Poster: Triangle centers

Long time ago some curious person drew a triangle in the sand and bisected the three angles. He noted that the bisectors met in a single point and decided to repeat the experiment using perpendicular bisectors, medians and altitudes. Astonished, the person discovered that in every experiment the lines intersected at one point. These four point were given the following names: incenter, centroid, circumcenter, and orthocenter.

Click on the thumbnail to enlarge the poster

### Lesson 4-1 Classifying Triangles

A triangle has three sides and three angles.

The three angles always add to 180°

Triangles can be classified either

**According to their sides**

There are three special names given to triangles that tell how many sides are equal.

**or according to their angles**

Triangles can also have names that tell you what type of angle is inside:

**Combining the Names**

Sometimes a triangle will have two names, for example:

**Short video about triangles**

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