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Geometry. Trapezoids and Isosceles Trapezoids. Quadrilateral. A closed figure with 4 sides. Parallelogram. Kite. Trapezoid. Rhombus. Rectangle. Isosceles Trapezoid. Square. The Quadrilateral Family. Trapezoid. Isosceles Trapezoid. Trapezoids.
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Geometry • Trapezoids and Isosceles Trapezoids
Quadrilateral A closed figure with 4 sides Parallelogram Kite Trapezoid Rhombus Rectangle Isosceles Trapezoid Square The Quadrilateral Family Trapezoid Isosceles Trapezoid
Trapezoids A Trapezoid is a quadrilateral with only one pair of parallel sides.
Base Leg Leg Base Terms to use with Trapezoids The two parallel sides are called bases. The two non-parallel sides are called legs. The angles at each end of a base are called base angles.
b m a Mid-line of a TrapezoidMidline of a trapezoid is the segment joining the midpoints of the legs. a m b The large quadrilateral is now a parallelogram as is the upper large quadrilateral and the lower large quadrilateral. So 2m = a + b and m = a + b 2 The length of the midline of a trapezoid is the average of the lengths of the bases.
Isosceles TrapezoidA trapezoid with congruent legs. Properties of an Isosceles Trapezoid. Both pairs of base angles are congruent. The diagonals are congruent.
Trapezoid? Isosceles Trapezoid? Trapezoid
Trapezoid? Isosceles Trapezoid? Neither
Trapezoid? Isosceles Trapezoid? Isosceles Trapezoid
Example 1 Find m∠F, m∠G, m∠H m∠F = 70° m∠G = 70° m∠H = 110°
Example 2 Solve for x. x = 1/2(17 + 21) x = 1/2(38) x x = 19
Example 3 Solve for x. 2x – 1 = 1/2(10 + 44) 2x – 1 = 1/2(54) 2x – 1 = 27 2x = 28 x = 14
Example 4 Solve for x. 32 = 1/2(4x + 43) 64 = 4x + 43 21 = 4x x = 21/4