A) 1. we expect to hear — him — the end — the month when the ship has reached kamchatka. 2. have you heard — the latest discovery made — the physics laboratory? 3. why take his words seriously? i am sure he said it all — fun. 4. if you are not sure — the spelling, look the word — — the dictionary.
5. i am — — him, i've had enough of his empty promises. 6. the trouble—that fellow is that he is interested — many things but good — nothing. 7. i don't advise you to mention the news — her, it will be all — the place — once. 8. why remind him — something he is trying so hard to forget? 9. they
hadn't been warned — the change and missed the first report. 10. he had missed a lot of lectures — the beginning — term and was working hard now to catch — — the rest—the group. 11. ann didn't stay — the end but rose to go long before the picture was —. she just couldn't stand it any more: — her
right sat a man who had been smoking all the time, — her left was a woman who had slept — the greater part — the film. 12. i am not sure i'll ever get used — his strange ways, but working-— him is a pleasure. 13. we'll be looking you — one of these days. 14. she didn't see how greatly disappointed
we were — her work. 15. it's impossible to keep all these facts — the head, i must make some notes. 16. as — grace, her parents didn't want her to take part — their long trip because that would mean missing a semester — college and be — the other students when she returned. 17. — first i called him
mr blake, but very soon he said: "leave — the 'mister', just call me plain blake." 18. as — the price he mentioned, no good businessman could make such an offer.
В параллелограмме сумма углов прилежащих к одной стороне равна 180°.
Следовательно ∠ B = 180°-60° = 120°.
Биссектриса делит угол B на два равных угла по 60°.
Сумма углов треугольника равна 180°, следовательно ∠AEB = 180°-60°-60° = 60°.
Следовательно треугольник ABE равносторонний со сторонами 75.
В параллелограмме противолежащие углы равны,
следовательно ∠С = ∠A = 60°.
Угол СFB = 180°- ∠C - ∠CBE = 180°-60°-60° = 60°.
Следовательно треугольник BCF равносторонний со сторонами 75.
∠FED и ∠AEB вертикальные и равны 60°
∠EDF = 180°-60°-60° = 60°.
Следовательно треугольник DFE равносторонний со стороной
BC-AE = 88-75 = 13.
EF = ED = DF = 13.
Ставьте лайки, подписывайтесь на мой канал!
Объяснение:
Радиус R=4 см.
Хорда АС=8 см. Следовательно хорда АС является диаметром окружности.
Угол, опирающийся на диаметр равен 90°. Вершина этого угла находится на окружности, значит этот угол вписанный и он равен половине градусной мере угла, на которую он опирается.
Исходя из этого, градусная мера дуги AmC равна 2*90°=180°.
или
диаметр отсекает половину окружности градусная мера которой 360°. Следовательно AmC=360°/2=180°.
***
Дуги АmC=60°. Значит вписанный угол АВС равен половине градусной мере дуги, на которую он опирается , т.е.30°. Тогда треугольник АВС - прямоугольный ∠АСВ=90°. Следовательно угол АСВ опирается на диаметр, половина которого равна АС=8 и диаметр равен D=2*АС=2*8=16.