Weba.90° b.80° c.70° d.60° 10、如图所示，顶角为36°的等腰三角形，其底边与腰之比等于 ，这样的三角形叫黄金三角形，已知腰长AB=1， ABC为第一个黄金三角形， BCD为第二个黄金三角形， CDE为第三个黄金三角形，以此类推，第2007个黄金三角形的周长为( ) Web28 apr. 2024 · Best answer It is given that BD = DC From the figure we know that ∠BCD = ∠CBD = 30o Consider BCD Using the angle sum property ∠BCD + ∠CBD + ∠CDB = 180o By substituting the values 30o + 30o + ∠CDB = 180o On further calculation ∠CDB = 180o – 30o – 30o By subtraction ∠CDB = 180o – 60o So we get ∠CDB = 120o

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Web10 sep. 2024 · (1) angle ABC = 30° (2) arc BQC = 160° The inscribed angle theorem states that " The measure of an inscribed angle is half the measure of its intercepted arc. So, we have, ∠ = 1/2 (m arc) Given, ∠ BAC = 80° m(arc APC) = 60° (1) angle ABC ∠ = 1/2 (m arc) ∠ ABC = 1/2 (m arc APC) = 1/2 × 60° ∴ ∠ ABC = 30° (2) arc BQC Web【推荐1】 一副三角板abc、dbe，如图1放置，（∠d＝30°、∠bac＝45°），将三角板dbe绕点b逆时针旋转一定角度，如图2所示，且0°＜∠cbe＜90°，则下列结论中正确的是（ ） ①∠dbc+∠abe的角度恒为105°； ②在旋转过程中，若bm平分∠dba，bn平分∠ebc，∠mbn的角度恒为定值； ③在旋转过程中，两块三角板 ... quotes about liking work

geometry - In ABC, D is the midpoint of AB, while E lies on BC ...

WebRegents Exam Questions Name: _____ G.CO.C.10: Interior and Exterior Angles of Triangles 1b www.jmap.org 2 9 In the diagram below, DE divides AB and AC proportionally, m∠C =26°, m∠A =82°, and DF bisects ∠BDE. The measure of angle DFB is 10 In the diagram below of triangle MNO, ∠M and ∠O are bisected by MS and OR, respectively. ... Web6 mei 2024 · In triangle ABC, DB and DC are angle bisectors and the angle BAC = 60° : Problem Solving (PS) Forum Home GMAT Quantitative Problem Solving (PS) Unanswered Active Topics Decision Tracker My Rewards New posts New comers' posts Round 2 decisions - Join Kellogg chat here! Events & Promotions Mar 28 From 250 to 780: A … Web∠BAC = 75° ∠ACB + 135° = 180° ∠ACB = 180° - 135° ∠ACB = 45° We know, sum of interior angles of triangle is equal to 180° ∠ABC + ∠BAC + ∠ACB = 180° Substituting the values ∠ABC + 75° + 45° = 180° ∠ABC + 120° = 180° So we get ∠ABC = 180° - 120° ∠ABC = 60° Therefore, the m∠ABC is 60°. What is the m∠ABC? Summary: shirley schmidt boston legal