As shown in the figure, in △ ABC, ab = 15, BC = 14, s △ ABC = 84 are known

As shown in the figure, in △ ABC, ab = 15, BC = 14, s △ ABC = 84 are known

(1) Let a be ad ⊥ BC at point D. ∵ s △ ABC = 12bc · ad = 84, ∵ 12 × 14 × ad = 84, ∵ ad = 12. Let B be ab = 15, ∵ BD = AB2 − ad2 = 152 − 122 = 9. ∵ CD = 14-9 = 5. In RT △ ADC, AC = ad2 + DC2 = 122 + 52 = 13, ∵ Tanc = ADDC = 125 (2) let B be ⊥ AC at point E. ∵ s △ ABC = 12ac · EB = 84, ∵ be = 16813, ∵ sin ∠ BAC = BEAB = 1681315 = 168195 = 5665

d like some soup?
1. Ask questions about some soup
2. Change the general question
3. Change the negative sentence

1.What do you like?
2.Do you like some soup?
3.I don't like soup.

It is known that the two right sides of a right triangle are a and B, and the hypotenuse is C (1). If a = 12, B = 5, find C, and use the arithmetic square root

c²=a²+b²=169=13²
So C = 13

Write antonyms or equivalents
left() west() south() near() here() on() different()
go() father() student() uncle()

Team answers
left(right) west(east) south(north) near(far) here(there) on(under) different(same) go(come) father(mother) student(teacher) uncle(aunt)

Let a, B and C be the three internal angles of a triangle, and the equation (SINB Sina) x2 + (Sina sinc) x + (sinc SINB) = 0 has equal roots, then the angle B ()
A. B＞60°B. B≥60°C. B＜60°D. B≤60°

A. The equation (SINB Sina) x2 + (Sina sinc) x + (sinc SINB) = 0 has equal roots, so △ = (Sina sinc) 2-4 (SINB Sina) (sinc SINB) = 0. According to the sine theorem: (A-C) 2-4 (B-A) (C-B) = A2 + c2-2ac-4 (bc-b2-ac + AB) = (A2 + C2 + 2Ac) - 4 (AB + BC) + 4B2 = (a + C) 2-4b (a + C) + 4B2 = (a + c-2b) 2 = 0, that is, a + C = 2B Therefore, D is selected because ∵ - 1 ∵ CoSb = A2 + C & nbsp; 2 − b22ac = (a + C) 2 − 2Ac − b22ac = 3B2 − 2ac2ac = 32 ° b2ac-1, ∵ (2b) 2 = (a + C) 2 ≥ 4ac, ∵ B2 ≥ AC,