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WAEC Mathematics Past Questions & Answers - Page 176

876.

which of the following statements describes the locus of a point R which moves in a plane such that its equidistant from two intersecting lines?

the bisector of the angle formed by the lines

the point of intersection of the two lines

A cone, with two intersecting lines as slant height

A circle, with the point of intersection of the two lines as the center

View answer & explanation

Correct answer is A

No explanation has been provided for this answer.

877.

An arc of a circle of radius 14cm subtends angle 300^o at the center. Find the perimeter of the sector formed by the arc

14.67cm

42.67cm

101.33cm

543.33cm

View answer & explanation

Correct answer is C

The perimeter of the sector $=2r+\frac{\theta}{360}\times 2\pi r \\ \Rightarrow 28 + \frac{300}{360} \times \frac{2}{1} \times \frac{22}{7}\times \frac{14}{1} = \frac{220}{3}+28\\ 73.133+28=101.33cm$

878.

What is the total surface area of a closed cylinder of height 10cm and diameter 7cm? [Take $\pi = \frac{22}{7}$ ]

77cm²

227cm²

297cm²

374cm²

View answer & explanation

Correct answer is C

T.S.A of s closed cylinder = $2\pi r(r+h)\\ =\frac{2}{1}\times \frac{22}{7} \times \frac{7}{2}\left(\frac{7}{2}+\frac{10}{1}\right)=\frac{22}{1}\left(\frac{27}{2}\right)=27\times 11=297cm^2$