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3 years ago

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Using the formula C = 2πr, find the circumference of a circle with diameter of 28 inches. Round your answer to the nearest inch.

A. 44 in. B. 56 in. C. 88 in. D. 28 in.

2 answers:

sweet-ann [11.9K]3 years ago

7 0

It’s C) 88in because 28 x 3.14 = 87.92 = 88
Hope this helped

Maurinko [17]3 years ago

7 0

The answer to your question is the letter C

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The sum of two terms of gp is 6 and that of first four terms is 15/2.Find the sum of first six terms.

Gnoma [55]

Given:

The sum of two terms of GP is 6 and that of first four terms is $\dfrac{15}{2}.$

To find:

The sum of first six terms.

Solution:

We have,

$S_2=6$

$S_4=\dfrac{15}{2}$

Sum of first n terms of a GP is

$S_n=\dfrac{a(1-r^n)}{1-r}$ ...(i)

Putting n=2, we get

$S_2=\dfrac{a(1-r^2)}{1-r}$

$6=\dfrac{a(1-r)(1+r)}{1-r}$

$6=a(1+r)$ ...(ii)

Putting n=4, we get

$S_4=\dfrac{a(1-r^4)}{1-r}$

$\dfrac{15}{2}=\dfrac{a(1-r^2)(1+r^2)}{1-r}$

$\dfrac{15}{2}=\dfrac{a(1+r)(1-r)(1+r^2)}{1-r}$

$\dfrac{15}{2}=6(1+r^2)$ (Using (ii))

Divide both sides by 6.

$\dfrac{15}{12}=(1+r^2)$

$\dfrac{5}{4}-1=r^2$

$\dfrac{5-4}{4}=r^2$

$\dfrac{1}{4}=r^2$

Taking square root on both sides, we get

$\pm \sqrt{\dfrac{1}{4}}=r$

$\pm \dfrac{1}{2}=r$

$\pm 0.5=r$

Case 1: If r is positive, then using (ii) we get

$6=a(1+0.5)$

$6=a(1.5)$

$\dfrac{6}{1.5}=a$

$4=a$

The sum of first 6 terms is

$S_6=\dfrac{4(1-(0.5)^6)}{(1-0.5)}$

$S_6=\dfrac{4(1-0.015625)}{0.5}$

$S_6=8(0.984375)$

$S_6=7.875$

Case 2: If r is negative, then using (ii) we get

$6=a(1-0.5)$

$6=a(0.5)$

$\dfrac{6}{0.5}=a$

$12=a$

The sum of first 6 terms is

$S_6=\dfrac{12(1-(-0.5)^6)}{(1+0.5)}$

$S_6=\dfrac{12(1-0.015625)}{1.5}$

$S_6=8(0.984375)$

$S_6=7.875$

Therefore, the sum of the first six terms is 7.875.

5 0

3 years ago

A class trip was 234 miles away from the school. If the bus driver drove at a constant speed of 70 mph, about how long did the t

galina1969 [7]

C. <span>3 hours 34 minutes

Divide:
234 ÷ 70 = 3.34

Your answer is C

♥ Hope I helped ♥</span>

7 0

3 years ago

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PLEASE HELP FAST!!

sertanlavr [38]

Answer:

104

Step-by-step explanation:

15 x 14= 210 divide by 2

105

180 - 105 = 75

15 + 14 + 75 = 104

5 0

3 years ago

Which value must be added to the expression x2 – 3x to make it a perfect-square trinomial?

Vitek1552 [10]

Answer:

$\frac{9}{4}$

Step-by-step explanation:

Given

x² - 3x

To make the expression a perfect square

add ( half the coefficient of the x- term )²

x² + 2( - $\frac{3}{2}$ )x + $\frac{9}{4}$ , thus

x² - 3x + $\frac{9}{4}$

= (x - $\frac{3}{2}$ )² ← a perfect square

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3 years ago

If x < 0 and y > 0, where is the point located

Solnce55 [7]

Answer:

rwrrwrwrr

Step-by-step explanation:

wrrwrrw

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3 years ago

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