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Maths
GCSE

How do you calculate the sine, cosine and tangent values for 45 degrees without a calculator?

To find the values for 45 degrees, we construct a right angled isosceles triangle, which has two sides of equal length. We can say that these sides are 1 unit long, and so we can figure out the value of t...

Answered by Heather C. Maths tutor
17918 Views

I decrease a number by 26%, the answer is 9 x10^-7, what was the original number?

The number has been decreased by 26%, this means that the original number is 100-26=74% of the original value. 

Therefore 9 x 10-7 = 0.74 x N, where N is the original number.

Henc...

Answered by Luke C. Maths tutor
3464 Views

expand and simplify (x+3)(x-7)

(x+3)(x-7)

= (xx) + (x-7) + (x3) + (3-7)

= x^2 - 7x + 3x - 21

= x^2 - 4x - 21

Key here is to ensure you multiply each term in one bracket by both in the other...

Answered by Luke P. Maths tutor
22818 Views

How do I use Pythagoras' Theorem to calculate the hypotenuse of a triangle?

[use of board] So, Pythagoras' theorem states that a^2+b^2=c^2. Therefore, we need to mark the triangle with a, b &c. a and b do not matter, c must be the longest edge, that creates the diagonal. Put ...

Answered by Cathy T. Maths tutor
3082 Views

Triangle ABC is a triangle with a right angle at vertex B. Length BC = 6cm and angle A = 30 degrees. How long is length AC?

Draw the triangle. BC is opposite to the angle given and we need to find the hypotenuse. Using SOHCAHTOA, we must use sine. Rearrange to find hypotenuse and then put the numbers in. Length AC = 12cm

Answered by Courtney C. Maths tutor
3019 Views

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