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DWP #62

3/16/15 8-3 B Quadrilaterals

and Angle Sums

5 Types of Quadrilaterals-closed figure with four straight sides

1. Parallelogram2. Rectangle3. Rhombus4. Square5. Trapezoid

Parallelogram

• Opposite sides parallel• Opposite sides congruent• Opposite angles congruent

• Opposite sides parallel• Opposite sides and angles congruent

• Four right angles

Sound Familiar?

Rhombus

• Opposite sides parallel• Opposite sides and angles congruent

• ALL SIDES congruent

Sound Familiar?

Square

• A rectangle with four congruent sides

Trapezoid

• One pair of parallel sides (bases)

Fun Fact

• In every quadrilateral there are 2 Triangles!

The sum of the angles of a triangle is 180 degrees.

ALWAYS!

Remember there are 2 triangles in a quadrilateral….

Using that information how could we find the angle sum of a quadrilateral?

There are two triangles... Because the sum of the angles of each triangle is 180 degrees...

We get 180 + 180 = 360

So, the sum of the interior angles of a quadrilateral is 360 degrees. ALWAYS!!!!!!

Again…

• The sum of the angles in any quadrilateral is always 360o.

• We can use this fact to find missing angle measures in quadrilaterals.

Let’s Practice

• Ex. 1: Classify the figure. Find the missing angle measure.

Solution Ex.1

• Trapezoid

109 + 86 + 71 + b = 360 195 + 71 + b = 360

266 + b = 360 - 266 -266

b = 94o

Let’s Check :109 + 86 + 71 + 94 = 360

Ex. 2

Classify the figure. Find the missing angle measure.

Solution Ex.2

• Quadrilateral

82 + 51 + 113 + x = 360 133 + 113 + x = 360246 + x = 360 - 246 -246 x = 114o

Let’s Check :82 + 51 + 113 + 114 = 360

Exit Ticket•Pg. 470 # 1-10 Odds

Homework

• Pg. 470 #1-30 Evens