Draw a diagram to illustrate the truth of the algebraical identity \[ (a-b)(a+b) = a^2-b^2. \] \item[*3.] Prove that the angle at the centre of a circle is double any angle at the circumference standing on the same arc.
Prove that the internal bisector of an angle of a triangle divides the opposite side in the ratio of the sides containing the bisected angle.
A milkman buys eggs at 10 for 3s. and sells them at \(4\frac{1}{2}\)d. each; what is his profit per cent.?
A man sells out £800 of Swedish Bonds at \(118\frac{1}{4}\) and reinvests the proceeds in five per cent. National War Bonds at par; what income does he now receive?
Simplify:
At an election the majority was 1184, which was one-fifth of the total number of votes; how many votes did each side poll?
Find the sum of 24 terms of the series \(4\frac{1}{2}+3\frac{3}{4}+3+\dots\). The sum of eight terms of an arithmetical progression is 24 and its fifth term is 1; find the first term and the common difference.