As shown in the figure, in trapezoidal ABCD, ∠ d = 90 ° and M is the midpoint of ab. if cm = 6.5 and BC + CD + Da = 17, the area of trapezoidal ABCD is () A. 20B. 30C. 40D. 50

RELATED INFORMATIONS

• 1. As shown in the figure, in ladder ABCD, AB is parallel to DC, point E is the midpoint of DC, ∠ AED = ∠ BEC, proving that ladder ABCD is isosceles ladder
• 2. In rectangular trapezoid ABCD, ab ∥ CD, ab ⊥ ad, and ab = 13, CD = 8, ad = 12, then the distance from point a to BC is______ ．
• 3. In the right angle trapezoid ABCD, ab ∥ CD, Da is vertical AB, ab = 13, CD = 8, ad = 12, then what is the distance from point a to BC?
• 4. As shown in the figure, in the rectangular trapezoid ABCD, the bottom AB = 13, CD = 8, ad ⊥ AB and ad = 12, then the distance from a to BC is () A. 12B. 13C. 12×2113D. 10.5
• 5. It is known that in the trapezoidal ABCD, ad ‖ BC, AB: BC: CD: Da = 4:5:3:2, if BC-AD = 9, the lengths of AB and DC are obtained
• 6. As shown in the figure, in rectangular trapezoid ABCD, ab ∥ CD, ad ⊥ DC, ab = BC, and AE ⊥ BC. (1) prove: ad = AE; (2) if ad = 8, DC = 4, find the length of ab
• 7. As shown in the figure, in rectangular trapezoid ABCD, ab ∥ CD, ad ⊥ DC, ab = BC, and AE ⊥ BC. (1) prove: ad = AE; (2) if ad = 8, DC = 4, find the length of ab
• 8. In rectangular trapezoid ABCD, ab ∥ CD, ad ⊥ DC, ab = BC, and AE ⊥ BC
• 9. As shown in the figure, in the trapezoidal ABCD, AD / / BC, ∠ ABC = 60 °. ∠ DCB = 30 ° AB = 4, find BC ad
• 10. Trapezoid ABCD is right angle trapezoid, AB / / DC, ∠ DAB = 90 °, PA ⊥ plane ABCD, and PA = ad = DC = & frac12; ab = 1, M is the midpoint of Pb, find the dihedral angle formed by plane AMC and plane BMC
• 11. In trapezoidal ABCD, if ab ‖ CD, point E is the midpoint of AD and s △ BEC = 2, then the area of trapezoidal ABCD is______ ．
• 12. In ladder ABCD, AD / / BC, DC / / BC, e are the midpoint of ab It's BC ⊥ DC
• 13. As shown in the figure, ladder ABCD, e is the midpoint of AB, DC = AD + BC, prove de ⊥ EC
• 14. In the trapezoidal ABCD, ab ‖ CD, ∠ a = 90 °, ab = 2, BC = 3, CD = 1, e is the midpoint of AD. try to judge the position relationship between EC and EB, and write the inference
• 15. In the isosceles trapezoid ABCD, AD / / BC, AB / / DC, point E is a point in the trapezoid, and EA = ed, EB = EC is proved
• 16. As shown in the figure, in trapezoidal ABCD, ad ∥ BC, ab = DC, AE ⊥ BC at point E, the vertical bisector GF of AB intersects BC at point F, intersects AB at point G, and connects AF. it is known that ad = 1.4, AF = 5, GF = 4. (1) calculate the waist length of trapezoidal ABCD; (2) calculate the area of trapezoidal AFCD
• 17. In trapezoidal ABCD, ab ‖ CD, f is the midpoint of BC, and AF ⊥ ad, e is on CD, satisfying AF = EF. (1) verification: 12 ∠ AFE + ∠ d = 90 °; (2) connecting AE, if ad = 5, AF = 6, finding the length of AE
• 18. In the trapezoid ABCD, ad ∥ BC, BF = FG = GC, it is proved that AP: FP = AF: ef (P is a point under the bottom edge of the trapezoid, AP intersects at point F through BC, DP intersects at point G through BC, and the intersection of BD and AP is e) BC is a trapezoid. The bottom (long) edge of ABCD is below the trapezoid, that is, BC
• 19. As shown in the figure, it is known that: in trapezoidal ABCD, ad ‖ BC, e is the midpoint of AC, connecting de and extending BC to point F, connecting AF. (1) verification: ad = CF; (2) under the condition that the original condition remains unchanged, please add another condition (no additional auxiliary line), so that the quadrilateral AFCD becomes a diamond, and explain the reason
• 20. As shown in the figure, in ladder ABCD, AB is parallel to CD, ad = BC, EF are AD.BC BD bisection ∩ ABC is called EF at point G, eg = 18, FG = 10 to find the trapezoid perimeter