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3 years ago

Rationalise the denominator 5 by√7-√5

Mathematics

1 answer:

taurus [48]3 years ago

4 0

i wasn't sure on how to explain it so i just attached ur answer

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Rebecca and dan are biking in a national park for three days they rode 5 3/4 hours the first day and 6 4/5 hours the second day

AfilCa [17]

Answer:

Rebecca and Dan need to ride $7\frac{9}{20}\ hrs.$ on the third day in order to achieve goal of biking.

Step-by-step explanation:

Given:

Goal of Total number of hours of biking in park =20 hours.

Number of hours rode on first day = $5\frac34 \ hrs.$

So we will convert mixed fraction into Improper fraction.

Now we can say that;

To Convert mixed fraction into Improper fraction multiply the whole number part by the fraction's denominator and then add that to the numerator,then write the result on top of the denominator.

$5\frac34 \ hrs.$ can be Rewritten as $\frac{23}{4}\ hrs$

Number of hours rode on first day = $\frac{23}{4}\ hrs$

Also Given:

Number of hours rode on second day = $6\frac45 \ hrs$

$6\frac45 \ hrs$ can be Rewritten as $\frac{34}{5}\ hrs.$

Number of hours rode on second day = $\frac{34}{5}\ hrs.$

We need to find Number of hours she need to ride on third day in order to achieve the goal.

Solution:

Now we can say that;

Number of hours she need to ride on third day can be calculated by subtracting Number of hours rode on first day and Number of hours rode on second day from the Goal of Total number of hours of biking in park.

framing in equation form we get;

Number of hours she need to ride on third day = $20-\frac{23}{4}-\frac{34}{5}$

Now we will use LCM to make the denominators common we get;

Number of hours she need to ride on third day = $\frac{20\times20}{20}-\frac{23\times5}{4\times5}-\frac{34\times4}{5\times4}= \frac{400}{20}-\frac{115}{20}-\frac{136}{20}$

Now denominators are common so we will solve the numerator we get;

Number of hours she need to ride on third day = $\frac{400-115-136}{20}=\frac{149}{20}\ hrs \ \ Or \ \ 7\frac{9}{20}\ hrs.$

Hence Rebecca and Dan need to ride $7\frac{9}{20}\ hrs.$ on the third day in order to achieve goal of biking.

3 0

3 years ago

If x = a sin α, cos β, y = b sin α.sin β and z = c cos α then (x²/a²) + (y²/b²) + (z²/c²) = ?

Oduvanchick [21]

$\large\underline{\sf{Solution-}}$

Given:

$\rm \longmapsto x = a \sin \alpha \cos \beta$

$\rm \longmapsto y = b \sin \alpha \sin \beta$

$\rm \longmapsto z = c\cos \alpha$

Therefore:

$\rm \longmapsto \dfrac{x}{a} = \sin \alpha \cos \beta$

$\rm \longmapsto \dfrac{y}{b} = \sin \alpha \sin \beta$

$\rm \longmapsto \dfrac{z}{c} = \cos \alpha$

Now:

$\rm = \dfrac{ {x}^{2} }{ {a}^{2}} + \dfrac{ {y}^{2} }{ {b}^{2} } + \dfrac{ {z}^{2} }{ {c}^{2} }$

$\rm = { \sin}^{2} \alpha \cos^{2} \beta + { \sin}^{2} \alpha \sin^{2} \beta + { \cos}^{2} \alpha$

$\rm = { \sin}^{2} \alpha (\cos^{2} \beta + \sin^{2} \beta )+ { \cos}^{2} \alpha$

$\rm = { \sin}^{2} \alpha \cdot1+ { \cos}^{2} \alpha$

$\rm = { \sin}^{2} \alpha + { \cos}^{2} \alpha$

$\rm = 1$

Therefore:

$\rm \longmapsto\dfrac{ {x}^{2} }{ {a}^{2}} + \dfrac{ {y}^{2} }{ {b}^{2} } + \dfrac{ {z}^{2} }{ {c}^{2} } = 1$

5 0

3 years ago

Pls help due in 10 mins

nikitadnepr [17]

Answer:

Area = 97.4 cm²

Step-by-step explanation:

a = 15 cm

$Area = \frac{ \sqrt 3}{4} a^2\\$

$=\frac{\sqrt 3}{ 4 } \times 15^2\\\\=\frac{\sqrt 3}{ 4 } \times 225\\\\= 97.4 \ cm^2$

8 0

3 years ago

Joan says that the expression

Gemiola [76]

Answer:

Yes, Joan is correct

Explanation

3 0

3 years ago

Kimora’s cell phone company charges her $35 a month for phone service plus $.05 for each text message sent. How many text messag

professor190 [17]

Given that Kimora’s cell phone company charges her $35 a month for phone service plus $.05 for each text message sent.

Kimora's cell phone bill for one month is $52.

We need to determine the number of text messages Kimora sent for one month.

Also, we need to write and equation and solve it.

The equation:

Let x denote the number of text messages Kimora sent for one month.

Thus, the equation is given by

$35+0.05x=52$

Therefore, the equation for the number of text messages Kimora sent for one month is $35+0.05x=52$

Solving the equation:

We need to solve the equation $35+0.05x=52$

Subtracting both sides of the equation by 35, we get;

$0.05x=17$

Dividing both sides of the equation by 0.05, we get;

$x=340$

Therefore, the number of messages sent is 340.

3 0

3 years ago