58. A cone has a volume of [tex][tex]$1256 \, \text{cm}^3$[/tex][/tex]. The vertical height of the cone is 14 cm. Find the radius of the cone. (Use [tex]3.142[/tex])

A. [tex]9.1 \, \text{cm}[/tex]

B. [tex]9.3 \, \text{cm}[/tex]

C. [tex]9.8 \, \text{cm}[/tex]

D. [tex]9.3 \, \text{cm}^2[/tex]

59. Solve [tex]\frac{2}{3} - \frac{1}{y} = \frac{5}{y}[/tex]

A. 7

B. 5

C. 9

D. 11

60. Change [tex]\frac{23}{7}[/tex] to a mixed fraction.

A. [tex]2 \frac{3}{7}[/tex]

B. [tex]3 \frac{2}{7}[/tex]

C. [tex]3 \frac{1}{7}[/tex]

D. [tex]2 \frac{1}{7}[/tex]



Answer :

Let's address each question one by one.

### Question 58:
A cone has a volume of [tex]\(1256 \, \text{cm}^3\)[/tex], and the height [tex]\(h\)[/tex] of the cone is 14 cm. Find the radius of the cone. The value of [tex]\(\pi\)[/tex] is 3.142.

Given:
- Volume [tex]\(V = 1256 \, \text{cm}^3\)[/tex]
- Height [tex]\(h = 14 \, \text{cm}\)[/tex]
- [tex]\(\pi = 3.142\)[/tex]

The formula for the volume of a cone is:
[tex]\[ V = \frac{1}{3} \pi r^2 h \][/tex]

Rearrange the formula to solve for [tex]\(r\)[/tex]:
[tex]\[ r^2 = \frac{3V}{\pi h} \][/tex]

Substitute the given values into the formula:

[tex]\[ r^2 = \frac{3 \times 1256}{3.142 \times 14} \][/tex]

Let's denote the radius squared as [tex]\(r^2\)[/tex]:

[tex]\[ r^2 = 85.65972537964899 \][/tex]

Taking the square root of both sides to solve for [tex]\(r\)[/tex]:

[tex]\[ r = \sqrt{85.65972537964899} \approx 9.255253933828557 \, \text{cm} \][/tex]

Among the given choices, the closest value to [tex]\(9.255253933828557 \, \text{cm}\)[/tex] is:

B. [tex]\(9.3 \, \text{cm}\)[/tex]

### Question 59:
Solve [tex]\(\frac{2}{3} - \frac{1}{y} = \frac{5}{y}\)[/tex]

First, combine the terms involving [tex]\(y\)[/tex] on one side of the equation:

[tex]\[ \frac{2}{3} = \frac{5}{y} + \frac{1}{y} \][/tex]

Combine the fractions on the right side:

[tex]\[ \frac{2}{3} = \frac{5+1}{y} \][/tex]
[tex]\[ \frac{2}{3} = \frac{6}{y} \][/tex]

To clear the fraction, multiply both sides by [tex]\(y\)[/tex]:

[tex]\[ y \cdot \frac{2}{3} = 6 \][/tex]

Multiply both sides by [tex]\(3\)[/tex] to clear the denominator:

[tex]\[ 2y = 18 \][/tex]

Divide both sides by [tex]\(2\)[/tex]:

[tex]\[ y = 9 \][/tex]

So, the solution is:

D. [tex]\(9\)[/tex]

### Question 60:
Change [tex]\(\frac{23}{7}\)[/tex] to a mixed fraction.

First, divide [tex]\(23\)[/tex] by [tex]\(7\)[/tex]:

[tex]\[ 23 \div 7 = 3 \text{ remainder } 2 \][/tex]

So, [tex]\(\frac{23}{7}\)[/tex] can be written as:

[tex]\[ 3 \frac{2}{7} \][/tex]

The answer is:

A. [tex]\(3 \frac{2}{7}\)[/tex]

In summary, the answers are:
- Q58: B. [tex]\( \quad 9.3 \, \text{cm} \)[/tex]
- Q59: D. [tex]\( 9 \)[/tex]
- Q60: A. [tex]\( 3 \frac{2}{7} \)[/tex]