If a triangle has sides of 7 cm and it is an equilateral you can draw a line right down the middle to form two congruent triangles.
These smaller triangles have a hypotenuse of 7cm and a base of 3.5 cm (7/2)
To work out the height, use Pythagoras’ theorem.
a^2 + b^2 = c^2 where c is the hypotenuse and a and b are the other two sides
7^2 - 3.5^2 = 36.75
Square root answer
= 6.06 cm
That’s the height of the triangle
Area of a triangle is base x height divided by 2
So 7 x 6.06 = 42.43…
/2
= 21.2 cm^2 to one d.p
Hope this helped!
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A
Given a quadratic in standard form : y = ax² + bx + c ( a ≠ 0 ), then
The x-coordinate of the vertex is
= - 
y = - 3x² + 2x - 7 is in standard form
with a = - 3, b = 2 and c = - 7, hence
= - 
= 
Substitute this value into the equation for y-coordinate
y = - 3 ()² + 2 ( ) - 7
= - + 
- 
= - 
vertex = ( , - ) → A
A) Muslims consider the Quran to be the holy book of Islam.
One
The sum of two rational numbers is always rational. sqrt(9) + sqrt(25) = 3 + 5 which is rational. sqrt(16/100) = 4/10 = 2/5 is also rational. 3/28 is rational as well.
Two
Those are irrational. sqrt(10) + pi = ???? You cannot reduce this to any kind of fraction. Two irrationals always give a rational.
Three
The irrational number controls the answer. 10 + sqrt(5) is irrational. The 10 is OK. It is raional, but sqrt(5) is not a rational number.
