Q. 34.0( 4 Votes )

# Prove that Use this to compute correct to two decimal places.

Answer :

(√2 + 1) (√2 – 1) = (√2)^{2} – (1)^{2} [∵ (a+b)(a-b) = a^{2}-b^{2}]

⇒ (√2 + 1) (√2 – 1) = 2 – 1

⇒ (√2 + 1) (√2 – 1) = 1

Hence, (√2 + 1) (√2 – 1) = 1

Now,

Rate this question :

We have seen in Class 7 that any odd number can be written as the difference of two perfect squares. (The lesson, **Identities**) Usingthis, draw lines of lengths centimetres.

The picture shows a tan gram of 7 pieces made by cutting a square of side 4 centimetres. Calculate the length of the sides of each piece.

Kerala Board Mathematics Part-1

Prove that Can you find other numbers like this?

Kerala Board Mathematics Part-1Prove that Use this to compute correct to two decimal places.

Kerala Board Mathematics Part-1Compute correct to two decimal places.

Kerala Board Mathematics Part-1The picture shows the vertices of a regular hexagon connected by lines.

i) Prove that the inner red hexagon is also regular.

ii) How much of a side of the large hexagon is a side of the small hexagon?

iii) How much of the area of the large hexagon is the area of the small hexagon?

Kerala Board Mathematics Part-1The hypotenuse of a right triangle is metres and another side is metre. Calculate its perimeter correct to a centimetre.

Kerala Board Mathematics Part-1The picture shows an equilateral triangle cut into halves by a line through vertex.

i) What is the perimeter of a part?

ii) How much less than the perimeter of the whole triangle is this?

Kerala Board Mathematics Part-1Calculate the length of the sides of the equilateral triangle on the right, correct to a millimetre.

Kerala Board Mathematics Part-1

Explain two different methods of drawing a line of length centimetres.

Kerala Board Mathematics Part-1