V = Sосн * h
Sосн = 1/2аb = 1/2 * 6 * 8 = 24
V = 24 * 5 = 120
14·12=168 СМ ПЛОЩАДЬ КОНВЕРТА
168÷42=4 СМ ПЛОЩАДЬ МАРКИ
Это легко
<span>3/6</span> ÷ <span>9/34</span> = <span>1·3/2·3</span> ÷ <span>9/34</span> = <span>1/2</span> ÷ 9/34 = <span>12</span> × <span>34/9</span> = <span>1·34/2·9</span> = <span>34/18</span> = <span>17·2/9·2</span> = <span>17/9</span> = <span>8 + 1·9/9</span> = <span>1 целая 8/9</span><span>
</span>98,6*1 целую 8/9
98 <span>6/10</span> × 1 <span>8/9</span> = 98 <span>3·2/5·2</span> × 1 <span>8/9</span> = 98 <span>3/5</span> × 1 <span>8/9</span> = <span>3 + 98·5/5</span> × <span>8 + 1·9/9</span> = <span>493</span> × <span>17/5*9</span> = <span>493·175·9</span> = <span>8381/45</span> = <span>11 + 186·45/45</span> = 186 <span>11/45
</span>
А на будущее есть калькулятор дробей
http://calc.by/math-calculators/fraction-calculator.html