Given the sequence {-500, -100, -20, -4, -0.8, ... }, we know that that the first term (a) is -500 and the ratio (r) is $\dfrac{-100}{-500}=\dfrac{1}{5}$

Input those values into the Sum formula:

$S_n=\dfrac{a(1-r^n)}{1-r}\\\\S_8=\dfrac{-500\bigg(1-\dfrac{1}{5}^n\bigg)}{1-\dfrac{1}{5}}\\\\.\quad=\dfrac{-500\bigg(1-\dfrac{1}{390,625}\bigg)}{\dfrac{4}{5}}\\\\.\quad=\dfrac{-500\bigg(\dfrac{390,624}{390,625}\bigg)}{\dfrac{4}{5}}\\\\.\quad=\dfrac{5(-500)(390,624)}{4(390,625)}\\\\.\quad=-624.998\\\\.\quad=-625\quad \text{(rounded to 2 decimal places)}$

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4 years ago

Si un cono lo obtienes haciendo girar un triángulo rectángulo cuya base es de 10cm y su altura es de 16cm ¿cuánto mide el radio

rodikova [14]

Answer:

10 cm.

Step-by-step explanation:

In order to better understand this question, I will attach an allusive image to the question.

Keep in mind that in this case the base of the triangle is equal to the radius of the base of the cone since the triangle rotates on its own axis, therefore the measurement of the base corresponds to 10 cm, therefore the radius measures 10 cm.