H^2=l^2-r^2
r=d/2=10/2=5
h^2=13^2-5^2= 169-25=144
h=√144=12
5(-1,4a+3)-(1-2,5a)-4(0,8a+3)=-7a+15-1+2,5a-3,2a-12=-7,7a-2
(315 + 621) / 9 + 107 * 6 = 746
315+621=936
936/9=104
107*6=642
104+642=746
746 + 1245 * 48 = 60506
1245*48=59760
746+59760=60506
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