Hi :) how to do question 7 ?

Step-by-step explanation:

We khow that the equation of a circle is written this way :

(x-a)²+(y-b)²=r² where (x,y) are the coordinates of the cercle's points and (a,b) the coordinates of the cercle's center and r the radius .

Our task is to khow the values of a and b :

We khow that the center is lying on the line 3x+2y=16⇒ 2y=-3x+16⇒ y= x+8  We khow that the points P and Q are two points in the cercle Let Ω be the center of this cercle we can notice that : PΩ AND QΩ are both equal to the radius ⇒ PΩ=QΩ= rSo let's write the expression of this distance using vectors KHOWING THAT Ω(a,b)Vector PΩ(a-4,b-6) and Vector QΩ(a-8,b-2) PΩ=and QΩ=Let's substitute a by x and b by y PΩ=QΩ we substitute each distance by its expression After simplyfying the expressions we get finally : -12+8x-8y=0 now we have -12x +8x-8y=0 and the line equation 3x+2y-16=0 these are simultanious equations so after solving them we get x=3.8 wich is approximatively 4 and y=2 we substitute a by 4 and y by 2 in PΩ to get the radius we get r = = 4 so r²= 16 then the equation is : (x-4)²+(y-2)²=16

Answer: d. 39 cmin the diagram, the approximate length of the minor arc de is 39 centimetres.step-by-step explanation: the formula for the length of an arc in a circle is as displayed below.let the length of the minor arc de = xx = 2( pi )r × angle of sector / 360°from this, we will substitute the values given from the problem into the formula to obtain the length of the minor arc de.x = 2( pi )r × angle of sector / 360°r = radius = 25cmpi as an approximate value = 3.14angle of sector = 120°x = 2( 3.14 )( 25 ) × 120° / 360°x = 157 × 1 / 4x = 39.25x = 39 ( rounded to the nearest whole number as an approximate value )