Скачать или смотреть THEOREMS ON TRAPEZOIDS & MIDSEGMENT THEOREM | GRADE 9

Study the different theorems on trapezoid and the midsegment theorem
A trapezoid is a convex quadrilateral with exactly one pair of parallel sides.
The bases of a trapezoid are the two parallel sides.
The legs of a trapezoid are the two non-parallel sides.
An isosceles trapezoid is a trapezoid with congruent legs.
The median of a trapezoid is the segment that joins the midpoints of the legs.

Theorem 6: The median of a trapezoid is parallel to each base and its length is one half the sum of the lengths of the bases.
•Theorem 7: The base angles of an isosceles trapezoid are congruent.
•Theorem 8 : The opposite angles of an isosceles trapezoid are supplementary.
•Theorem 9: The diagonals of an isosceles trapezoid are congruent.

Sample Exercises:
Given: Quadrilateral MATH is an isosceles trapezoid with bases MA and HT, LV is a median
1. Given: MA = 3y – 2; HT = 2y + 4; LV = 8.5 cm.
Questions:
• What is the value of y?
• How did you solve for y?
• What are MA and HT?
2. Given: angle HMA = 115
Questions:
• What is m angle TAM?
• What theorem justifies your answer?
3. Given: angle MHT = 3x + 10; angle MAT = 2x – 5
Questions:
• What is the value of x?
• How did you solve for x?
• What are the measures of the two angles?
• What theorem justifies your answer?
4. Given: AH = 4y – 3; MT = 2y +5
Questions:
• What is the value of y?
• How did you solve for y?
• How long is each diagonal?
• What theorem justifies your answer?