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Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides. Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent. Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides
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Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent - diagonals bisect the angles at the vertex B A C D
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent - diagonals bisect the angles at the vertex - diagonals bisect each other and are perpendicular B A E C D
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent - diagonals bisect the angles at the vertex - diagonals bisect each other and are perpendicular B A E 14 C 60° D EXAMPLE : If AD = 14, what is the measure of EB ?
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent - diagonals bisect the angles at the vertex - diagonals bisect each other and are perpendicular B A E 14 C 60° D EXAMPLE : If AD = 14, what is the measure of EB ? SOLUTION : With angle ADE = 60 degrees we have a 30 – 60 – 90 triangle. So segment EB = Segment ED which is half of AD.
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent - diagonals bisect the angles at the vertex - diagonals bisect each other and are perpendicular B A E 14 C 60° D EXAMPLE : If AD = 14, what is the measure of EB ? SOLUTION : With angle ADE = 60 degrees we have a 30 – 60 – 90 triangle. So segment EB = Segment ED which is half of AD. ED = 7
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent - diagonals bisect the angles at the vertex - diagonals bisect each other and are perpendicular B A E 14 C 60° D EXAMPLE : What is the measure of angle ECD ?
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent - diagonals bisect the angles at the vertex - diagonals bisect each other and are perpendicular B A E 14 C 60° D EXAMPLE : What is the measure of angle ECD ? SOLUTION : Again we have a 30 – 60 – 90 triangle. So angle DAC = 30 degrees.
Polygons – Rhombuses and Trapezoids Rhombus - four congruent sides - opposite angles are congruent - diagonals bisect the angles at the vertex - diagonals bisect each other and are perpendicular B A E 14 C 60° D EXAMPLE : What is the measure of angle ECD ? SOLUTION : Again we have a 30 – 60 – 90 triangle. So angle DAC = 30 degrees. So angle ECD would also be 30 degrees.
Polygons – Rhombuses and Trapezoids Trapezoid - two parallel sides that are not congruent ║ B A D C
Polygons – Rhombuses and Trapezoids Trapezoid - two parallel sides that are not congruent ║ • these parallel sides are called bases • - non-parallel sides are calledlegs base 1 B A leg leg D C base 2
Polygons – Rhombuses and Trapezoids Trapezoid - two parallel sides that are not congruent ║ • these parallel sides are called bases • - non-parallel sides are calledlegs base 1 B A leg leg D C base 2 - there are two pairs of base angles
Polygons – Rhombuses and Trapezoids Trapezoid - two parallel sides that are not congruent ║ • these parallel sides are called bases • - non-parallel sides are calledlegs base 1 B A leg leg D C base 2 • there are two pairs of base angles • diagonal base angles are supplementary
Polygons – Rhombuses and Trapezoids Trapezoid - two parallel sides that are not congruent ║ • these parallel sides are called bases • - non-parallel sides are calledlegs base 1 B A leg leg D C base 2 • there are two pairs of base angles • diagonal base angles are supplementary • base angles that share a leg are also supplementary
Polygons – Rhombuses and Trapezoids Isosceles Trapezoid - has all the properties of a trapezoid - legs are congruent - base angles are congruent A B D C
Polygons – Rhombuses and Trapezoids Isosceles Trapezoid - has all the properties of a trapezoid - legs are congruent - base angles are congruent - diagonals have the same length A B D C
Polygons – Rhombuses and Trapezoids Median of a Trapezoid - parallel with both bases - equal to half the sum of the bases - joins the midpoints of the legs A B X Y D C
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : What is the median length ? A 20 B D C 28
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : What is the median length ? A 20 B 24 D C 28
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : If AD = 18, what is the measure of AX ? A B 18 X Y D C
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : If AD = 18, what is the measure of AX ? The median joins the midpoints of the legs A B 18 X Y D C
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : ABCD is an isosceles trapezoid. If angle DAB = 110°, what is the measure of angle ABC ? A B D C
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : ABCD is an isosceles trapezoid. If angle DAB = 110°, what is the measure of angle ABC ? 110°- base angles are congruent in an isosceles trapezoid A B D C
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : What is the length of side AB? ? A B 40 X Y D C 50
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : What is the length of side AB? ? A B 40 X Y D C 50
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : What is the length of side AB? ? A B 40 X Y D C 50
Polygons – Rhombuses and Trapezoids Let’s try some problems… EXAMPLE : What is the length of side AB? ? A B 40 X Y D C 50