In triangle ABC, angle B = angle c = 36 degrees, angle ade = angle ade = 72 degrees, then the number of isosceles triangles in the graph is?

In triangle ABC, angle B = angle c = 36 degrees, angle ade = angle ade = 72 degrees, then the number of isosceles triangles in the graph is?

All triangles in the figure are isosceles triangles: △ ABC, △ abd, △ Abe, △ ade, △ ADC, △ ace, a total of 6
(the degree of other angles can be calculated according to the known angle.)

Given the angle man = 120 degrees, AC bisector angle man, angle ABC + angle ADC = 180 degrees, this paper proves whether AB + ad is equal to AC 3Q

On DM, take de = AB to connect EC as CF ⊥ am to F, CP ⊥ an to P, because ∠ ADC + ∠ ABC = 180 °∠ ADC + ∠ EDC = 180 °∠ EDC = ∠ ABC AC bisector angle man, so CF = CP ∠ CFD = ∠ CPB = 90 ° so △ CFD ≌ △ CPB CD = CB, ed = AB, ∠ EDC = ∠ ABC △ Dec ≌ △ BAC ∠ CED = ∠ cab = 60 ° and △ EAC is equilateral triangle, so AC = AE = AD + de = ad = ab

For a piece of land as shown in the figure, ad = 12M, CD = 9m, ∠ ADC = 90 °, ab = 39m, BC = 36m, calculate the area of this land

If AC is connected, in RT △ ADC, ac2 = Cd2 + ad2 = 122 + 92 = 225, х AC = 15; in △ ABC, AB2 = 1521, ac2 + BC2 = 152 + 362 = 1521, х AB2 = ac2 + BC2, х ACB = 90 degree, х s △ abc-s △ ACD = 12ac · bc-12ad · CD = 12 × 15 × 36-12 × 12 × 9 = 270-54 = 216