Need help on like 3 math problems. Give out 10 points to best answer.?

Question

1.Given 2 similar triangles, ABC and DEF, if AB = 7 and DE = 12 and AC = 8, then DF = ______. (Round to the nearest tenth.)
a.4.7
b.13.7
c.14.0

2. Given two circles, A and B, with radii 3 in. and 10 in. respectively, the ratio of the areas is

a.3/10 in.²
b.9/100 in.²
c.choices a and b are equivalent

Answer 1

Hi,
Qn 1) Similar triangles means they have the same ratios in terms of length, so for this example, you can work out ratios by comparing AB and DE with AC and DF.

Bear in mind that DEF is the bigger triangle.

Scale factor of DE to AB is 12/7.
So taking this scale factor and multiplying it with AC will give you the length of DF, which is :
(12/7) x 8
giving you 96/7
which when worked out, would be 13.714285....
since the answer is rounded to the nearest tenth, the answer would be 14.0. (actually that is the answer for the nearest unit, technically the nearest tenth would place the correct answer at 10, do check the question with your teacher)

Qn 2) Area of circle is π(r^2) where r is the radius

In this case, substituting values in:
Area of A = π (3^2)
= 9π

Area of B = π(10^2)
= 100π

Thus, the ratio of their areas would be:
(9π) / (100π)
cancelling out π,
we get 9/100.

Thus the answer for this question is (b). 9/100

Final answer:
Qn 1) (c) 14.0
Qn 2) (b) 9/100

Hope this helps. :D

Answer 2

1 a 2 a also

Answer 3

1. C.14.0
2. C. choices a and b are equivalent

#1 ab=7 and de=12 are the similar, the dif. between the two is 5. So, the side similar to ac=8, df= 5 more then 8 which is 14.0

#2 circle a has a radii of 3 in. and circle b has a radii of 10 in. The ratio (3/10) or (9/100) they are the same.

Answer 4

Are we talking legs or hypotenuses here? If you have to find the hypotenuse (ie, the longest side of the triangle), then use the Pythagorean theorem. Using ratios, (7:12 and 8:?) I'd have to say your best bet would be B, since 7 increases by 5 to give you 12, and 8 increased by 5 will give you 13. Similar triangles are triangles with matching angles, ie, all the same angles.

The second question is easy. The answer is A. Don't choose C or B, because 3/10 squared would be only 9/100, and not 9/100 squared. They are not equivalent.

I hope this helps.

Answer 5

1) 8 * 12/7 = 13.7, so B
2) area A = pi * 3² = 9 pi in.²
area A = pi * 10² = 100 pi in.²
So the ratio = 9/100 in.², so B
Note that answer C is definitely impossible as 3/10 = 0.3 and 9/100 = 0.09, so they're not equivalent.
3) This question is way too difficult for me.

Answer 6

1 "b"
think of it as 7 is to 12 as 8 is to ...
2 "a"

in #2 3/10 in.2 is the equiv. to 30/100 in.2 not 9/100 in.2, so "c" can't be it, as far as the other 2 answers, try using a compass and drawing them out, you'll see that one is approx. 1/3 the size of the other or "a" 3/10 in.2

Answer 7

a million) for this question, they're definitely speaking approximately gradient(or slope). Gradient is calculated by way of ability of "upward thrust divided by ability of Run" this is largely the vertical top divided by ability of the horizontal top. the way you calculate that and word to this question is calling the gradient of any 2 factors and evaluating it with the gradient of the different 2 factors, seeing in the event that they're the ssame. So for this reason, we could in basic terms evaluate (2, 9) and (-4, 8) with (-4, 8) and (7, 3). you could play around with which units of information factors you desire to comopare, yet undergo in techniques that throughout your assessment, there must be in basic terms one worry-unfastened information factor. To calculate gradient (or slope): we use the formulation: [y2 - y1] / [x2 - x1] the place x and y are the respective numbers in the information factors. in case you think of roughly it as a graph, you will discover which you're particularly calculating distances once you word the formulation. ok ur set: To calculate gradient for (2, 9) and (-4, 8): it is: (8-9) / (-4-2) = a million / (-6) which supplies -(a million/6). undergo in techniques this selection. To calculate gradient for (-4, 8) and (7, 3) it is: (3-8) / (7+4) = (-5) / (11) which supplies -(5/11), which doesnt experience the above sort of -(a million/6). observe that it is 7 + 4 for the reason which you're taking 7 minus (-4) in the formulation, for this reason providing you with 7 + 4. for this reason because of fact the gradients to not equate, the information factors do not instruct an instantaneous version. answer is (b) fake. Qn 2) this could be an common occasion. this is an common formulation so you might undergo in techniques: all promptly line graphs are denoted by ability of this universally: y = mx + c, the place: *y is the y fee *x is the x fee *m is the gradient (or fee of the slope) *c is the y-intercept. So by way of ability of staring on the equation you could particularly clean up for this question. in this question, the slope m is two/5 (in basic terms look on the selection previous the x), on the same time as the y-intercept c is -2. undergo in techniques you may desire to continually contain the sign (the two + or -) previous the selection. so the respond is (d) 2/5, -2 Qn 3) this question is such as question 2. for this reason the y-intercept is 0 on the same time as the slope is -(a million/3) so the respond is: (a) -a million/3, 0. it is because of fact the equation given in the question is largely: y = -a million/3 + 0 very final answer: a million(b); 2(d); 3(a). wish this facilitates. :D

Answer 8

answer to 1 is b. 13.7

AB squared/AC squared = DE squared/ DF squared

solving for DF = squareroot of (AC squared * DE squared/ AB squared)

squareroot of (64*144/ 49) = 13.7

answer to 2. is b. 9/100

area = piR squared

3*3/10*10 = 9/100

Answer 9

(AB/DE)*AC=13.7

Area is 2(3.14159)r, getting rid of the 2 pi we are left with (3/10). Note, there should be no units of square inches because this is a ratio, so in truth, all answers provided are incorrect, but (a) is closest to the correct answer.

Answer 10

answer 1 is b 13.7 and answer 2 is b 9/100 in. as for the third problem i would say give me the question and then i might be able to help