3/4x+3-2x=-1/4x+1/2x+5
3x+12-8x=-x+2x+20
-5x+12=x+20
-5x-x=20-12
-6x=8
-6x/-6=8/-6
X=8/-6
X=-4/3
Answer: The answers are (a) 40 cm and (b) 
Step-by-step explanation: The calculations are as follows:
(a) See the figure (a). As given in the question, A circle with centre 'O' circumscribes a triangle ABC with BC = 20 cm and ∠BAC = 30°. We need to find the diameter DC of the circle.
Let us draw BD. Now, ∠BAC and ∠BDC are angles on the same arc BC, so we have
∠BAC = ∠BDC = 30°.
Also, ∠CBD = 90°, since it stands on the diameter DC. So, ΔBCD will be a right angled triangle.
We can write

Thus, the diameter of the circle = 40 cm.
(b) See the figure (b).
As given in the question, A circle with centre 'O'' circumscribes a triangle DEF with EF = 4.6 inches and diameter GF = 12.4 in.. We need to find the angle EDF.
Let us draw GE. Now, ∠EGF and ∠EDF are angles on the same arc EF, so we have
∠EGF = ∠EDF = ?
Also, ∠GEF = 90°, since it stands on the diameter GF. So, ΔGEF will be a right angled triangle.
We can write

Thus,

To compare these two values, we need them to be in the same form.
To convert 20% into a decimal, we divide 20/100, or 0.20.
When comparing decimals, we know that 0.2 > 0.02.
Therefore, 20% > 0.02. (20% is greater than 0.02)
This sequence can be generated with this function, n being the nth member of the sequence:
f(n) = 0.25(n)