3 7/9 - 142/9 =34/9 - 142/9 = -108/9 = -12
(3 1/3 - 4,7) : 1/90 = (10/3 - 47/10) *90 = 300 - 47*9 = 300 - 423 = - 123
(1 1/4 - 95/32) : 5/96 = (5/4 - 95/32) * 96/5 = 96/4 - 95 * 96 / 32 * 5 = 24 - 3 * 19 = 24 - 57 = -33
(88 4/5 - 56 49/50): 3,7 = (88 40/50 - 56 49/50) * 10/37 = (4440/50 - 2849/50) * 10/37 =
= (1591/50)*10/37 = 1591 /5*37 = 8.6
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Пусть a=3; h=5
V = Sосн * h.
Sосн =
![\frac{3a^2 \sqrt{3} }{2} = \frac{27 \sqrt{3} }{2}](https://tex.z-dn.net/?f=+%5Cfrac%7B3a%5E2+%5Csqrt%7B3%7D+%7D%7B2%7D+%3D+%5Cfrac%7B27+%5Csqrt%7B3%7D+%7D%7B2%7D+)
тогда объем призмы
![V=5\cdot\frac{27 \sqrt{3} }{2}=\frac{135 \sqrt{3} }{2}](https://tex.z-dn.net/?f=V%3D5%5Ccdot%5Cfrac%7B27+%5Csqrt%7B3%7D+%7D%7B2%7D%3D%5Cfrac%7B135+%5Csqrt%7B3%7D+%7D%7B2%7D)
Площадь полной поверхности:
![S=3\cdot a^2\cdot \sqrt{3} +6\cdot a\cdot h=27 \sqrt{3} +90](https://tex.z-dn.net/?f=S%3D3%5Ccdot+a%5E2%5Ccdot+%5Csqrt%7B3%7D+%2B6%5Ccdot+a%5Ccdot+h%3D27+%5Csqrt%7B3%7D+%2B90)
Площадь боковой поверхности:
S = a * h * n= 3*5*6 = 90