Easy geometry problems solve...

Kya aap tenth pass se tej hein? .
Are u smarter than a tenth grade? check out.............!!!!!!

Solve these easy tenth level questions. for everyone.....

1. If triangles ABC and ABM are similar then LA + LD = ?

2. The sum of the squares of the medians of a triangle is (45 + 3/4) cm2.
The product of all the three respective sides are 72 cm3. If one of the
sides of a triangle is 3 cm. Then, find all the sides of the triangle.

3. Prove that the area of a sector is ∏ r2ѳ/360° and the length of the
arc is [2∏rѳ/360° - r2/2 sinѳ].

4. Prove that sec ѳ > 1, ѳ lies between 0 and pi/2

5. Prove that the sum of the squares of the sides of a parallelogram is equal to
the sum of the squares of its corresponding diagonals.

6. Show that for odd positive integer to be a perfect square, it should be of the form 8k + 1

7. Prove that 400289158 can be written as the sum of two squares.

8. Prove that a0 = 1

9. Prove that 1n + 8n - 6n - 3n is divisible by 10.

10. Prove that tangent to the circle at a point is perpendicular to the radius
of the circle through that point.

11.
AB is the tangent to the circle at point B. Prove that AB2 = AC x AD

14 Answers

62
Lokesh Verma ·

Are these your doubts rahul?

21
Shubhodip ·

6)every odd number is of the form (2n+1)
now (2n+1)2 = 4n2 + 4n +1
=4n(n+1) +1
=8k +1 [as, n(n+1) is divisible by 2!]

36
rahul ·

Exactly...

Well what do u say bout question 7.

36
rahul ·

Actually not sir!

Neither i hv posted this to check some one

It will simply help me boost up my problem solving skills

But How? -> I'll post it later on. [well know the solution to each and every problem]
posted above..

23
qwerty ·

11th is based on angles in alternate segments ( theorem in 10th std)

10th can be proved by assuming the opposite, and reaching a contradiction

i didnot undestand 1st one

36
rahul ·

1. Actually the first question is wrong.... don't feel bad over this please

11th will be proved by similarity if we join B with C and B with D

Then triangle BAC will be similar to triangle DAB [by AA criterion]

and so on............

But no one gave a try to Questions 2, 5, 7, 9

21
Shubhodip ·

9) its easy..write it as 8n-3n -(6n-1n) thus a multiple of 5

and 8n-6n-(3n-1n) multiple of 2

so divisible by 10

21
Shubhodip ·

5)

sum of squares of sides = 2(q2+p2) + 2a2

sum of squares of diagonals =(a-p)2 + (a+p)2 + 2q2

(ri8 angled triangles)

36
rahul ·

What have you done in question 5?.......

Solve it by plane geometry.....

ur solution is not at all clr.....!

36
rahul ·

Given : ||gm ABCD with diagonals AC and BD intersecting at O

Construction : We drop perpendiculars BM and DN from B and D and finally
triangle ADC can be represendted in the fig 2 clearly.

proof : Using pythagora's theorem,
AD2 + CD2 = 2DN2 + AN2 + CN2 = 2DN2 + (x + a)2 + (x - a)2
= 2 (DN2 + x2 + a2) = 2 (x2 + OD2)
but, x = OA = AC/2 and OD = BD/2
Thus, AD2 + CD2 = 2 (AC2 + BD2/4) = [AC2 + BD2]/2 ------------ (i)
similarly in triangle ABC we get,
AB2 + BC2 = [AC2 + BD2]/2 ------------------- (ii)

Adding eqns. (i) and (ii) we get....

AB2 + BC2 + CD2 + AD2 = AC2 + BD2 proved.......

36
rahul ·

proof for a0 = 1

a0 = am-m = am.a-m = am/am = 1 = R.H.S...

36
rahul ·

This is based on the fact that if a number on division by 4 leaves remainder 0,1 or 2
then it can be written as the sum of two squares or else not...

proof for this fact or theorem.....

any integer is either of the form 2k or 2k+1

Now, there are three cases:
Remainder when 4 divides the sum of the squares of
1. Two even integers.
2. One even and one odd integer.
3. Two odd integers.

Let's check out....

for the first case...

(2k)2 + (2k)2 = 8k2 -> remainder = 0 [when divided by 4]

for the second case

(2k)2 + (2k + 1)2 = 4k2 + 4k2 + 4k + 1 = 8k2 + 4k + 1 -> remainder = 1 [when divided by 4]

for the third case

(2k + 1)2 + (2k + 1)2 = 2(4k2 + 4k + 1) = 8k2 + 8k + 2 -> remainder = 2 [when divided by 4]

So we conclude that the sum of the squares of two positive integers leaves remainder 0,1 or 2 when divided by 4

Now on dividing 400289158 by 4 we get the remainder to be 2

and so it can be written as the sum of two squares proved....

wasn't that cool..............

21
Shubhodip ·

i solved that by pure geometry and was enough clear..

36
rahul ·

tha wasn't enough clr....k...!

u didn't show the methods.....

and no one can make that out simply by seeing your figure......!

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