AD =32 см ; BC =18 см ; AD || BC ; AB=BC ; апофема h =12 см .Без слов :2AB = AD +BC ⇔AB =(AD +BC)/2 r =(1/2)*√(AB ² - ((AD -BC)/2)² )= (1/2)*√(((AD +BC)/2) ² - ((AD -BC)/2)² ) =(1/2)√(AD*BC)r =(1/2)*√(32*18) =(1/2)*√(16*2*2*9) =4*3 =12 (см) . *********************** или ************************** ΔAOB (<AOB=90°) : r =√(AD/2*BC/2) ******************************************************d = √( h² -r²) = 0 ⇔ M ∈ (ABCD).: