CBSE Class 10 Answered
hi
![question image](http://images.topperlearning.com/topper/new-ate/top_mob16727204591942273307Screenshot_2023-01-01-20-10-38-94_439a3fec0400f8974d35eed09a31f914.jpg)
Asked by chaudahryanshika | 03 Jan, 2023, 10:04: AM
Question (5)
Quadratic equation :- a x2 + b x + c = 0
for real roots , b2 = ( 4 a c )
Given quadratic equation :- x2 + 4x + k= 0
a =1 , b = 4 , c = 1
b2 = 16
4 ac = 4 k = 16
Hence k = 4
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Question (6)
![](https://images.topperlearning.com/topper/tinymce/imagemanager/files/01e8e0187764f083b7c018aa5008ade363b3dd25278124.80333633f7.png)
As shown in figure , we gwt the sides of triangle as 4 unit, 3 unit and 5 unit.
Hence perimeter = 12 unit
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Question (7)
![](https://images.topperlearning.com/topper/tinymce/imagemanager/files/6ac04e014d938e5d62a28e7119d8bd0763b3e5f991ede4.26491857f8.png)
In a given similar triangles ABC and DEF
![begin mathsize 14px style fraction numerator A B over denominator D E end fraction equals fraction numerator B C over denominator F D end fraction space space space space t h e n space angle B space equals space angle D end style](https://images.topperlearning.com/topper/tinymce/cache/df55c74c83067489c1fb2f4e01bef0fc.png)
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Question (8) Partially hidden, unable to answer
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Question (9)
![begin mathsize 14px style angle A O B space equals space 130 degree end style](https://images.topperlearning.com/topper/tinymce/cache/aa66ad711f596ee45c23c7ee1ba45dca.png)
![begin mathsize 14px style angle P A O space equals space angle P B O space equals space 90 degree end style](https://images.topperlearning.com/topper/tinymce/cache/a7bb0548963542555206d734619ea6d5.png)
ΔOAB is isoceless because OA = OB
Hence ![begin mathsize 14px style angle O A B space equals space angle O B A space equals space 25 degree end style](https://images.topperlearning.com/topper/tinymce/cache/a6b55ebe8c5b7e3f18077d703f80ff49.png)
![begin mathsize 14px style angle O A B space equals space angle O B A space equals space 25 degree end style](https://images.topperlearning.com/topper/tinymce/cache/a6b55ebe8c5b7e3f18077d703f80ff49.png)
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Question (10)
![begin mathsize 14px style s e c space A space equals space fraction numerator 1 over denominator cos space A end fraction space equals space fraction numerator 1 over denominator square root of 1 space minus space sin squared A end root end fraction space equals space fraction numerator 1 over denominator square root of 1 space minus space open parentheses begin display style 1 half end style close parentheses squared end root end fraction space equals space fraction numerator 2 over denominator square root of 3 end fraction end style](https://images.topperlearning.com/topper/tinymce/cache/476e96c2ada345124b0863524eea0b07.png)
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Question (11)
![begin mathsize 14px style square root of 3 space cos squared A space plus space square root of 3 space sin squared A space equals space square root of 3 space open parentheses cos squared A plus sin squared A close parentheses equals space square root of 3 end style](https://images.topperlearning.com/topper/tinymce/cache/c4adf9bb67ae371b086b292bc0dcce44.png)
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Question (12)
cos1o cos2o cos3o ..........................cos88o cos89o cos90o = 0
because cos90 = 0 and ita ppears in product
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Question (13)
let r be the radius of circle. perimeter is ( 2
r )
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
If perimeter of square is ( 2
r ) then side of square ( 2
r )/4 = (
r )/2
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
Area of circle : area of square =
r2 : (1/4)
2 r2
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
Let us use
= 22/7 , then if simplify above ratio , we get areas are in the ratio 14 : 11
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
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Question (14)
area of circle is proportioanl to square of radius.
If radii of circle are in the ratio 4:3 , then areas are in the ratio 16:9
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Question (15)
Total surface area of solid hemisphere = 3
r2 = 3
×49 = 147
cm2
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
![begin mathsize 14px style pi end style](https://images.topperlearning.com/topper/tinymce/cache/6bef19d56ca8702b84be9f77acbea57c.png)
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Question 16
Modal class is between 15 to 20 , because frequency is highest for this class.
Upper limit is 20
Answered by Thiyagarajan K | 03 Jan, 2023, 14:26: PM
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