WAEC Past Questions and Answers - Page 2234

11,166.

A notebook of length 15 cm was measured to be 16.8 cm, calculate, correct to two d.p, the percentage error in the measurement.

A.

12.00%

B.

11.71%

C.

10.71%

D.

11.21%

Correct answer is A

Error = 16.8 - 15 = 1.8cm

% error = \(\frac{error}{ Actual value}\times 100%\)

=      \(\frac{1.8}{ 15}\times100%\)

=  \(0.12\times100%\)

   =   12.00%

11,167.

Find the gradient of the line passing through the points \((\frac{1}{2},  \frac{- 1}{3})  and  ( 3 , \frac{2}{3})\)

A.

\(\frac{2}{5}\)

B.

\(\frac{5}{2}\)

C.

\(\frac{2}{7}\)

D.

\(\frac{7}{2}\)

Correct answer is A

Gradient(slope) m = \(\frac{ y_2 - y_1}{ x_2 - x_1}\)

the points are  \((\frac{1}{2},  \frac{- 1}{3})  and  ( 3 , \frac{2}{3})\)

m = \(\frac{\frac{2}{3} - (\frac{-1}{3})}{3 - \frac{1}{2}}\)

=  \(\frac{\frac{2}{3} + \frac{1}{3}}{3 - \frac{1}{2}}\)

= \(1 \div\frac{5}{2}\) = \(1\times\frac{2}{5}\)           

Therefore, m = \(\frac{2}{5}\)

11,168.

Find the value of m in the diagram above.

A.

\(40^0\)

B.

\(50^0\)

C.

\(130^0\)

D.

\(140^0\)

Correct answer is C

∠EHI = ∠DEH = 40° (alternate angles are equal)
∠BEH = 90° (given)
∠BED = 90° - 40° = 50°
∠BEF = 180° - 50° = 130° (sum of angles on a straight line is 180o)
∠BEF = ∠ABE = 130° (alternate angles are equal)
∴ m = 130°

11,169.

In the diagram above, O is the centre of a circle NST. |NT| = |ST| and ∠NTS = 36°. Find the measure of the angle marked t.

A.

\(72^0\)

B.

\(54^0\)

C.

\(36^0\)

D.

\(108^0\)

Correct answer is C

t = ∠NTS (the angle between a tangent and a chord is equal to the angle in the alternate segment).

Therefore,  t = 36°

11,170.

The length of the diagonal of a square is 12 cm. Calculate the area of the square.

A.

\(36 cm^2\)

B.

\(48 cm^2\)

C.

\(72 cm^2\)

D.

\(18 cm^2\)

Correct answer is C

Let each side be l, then area = \(l^2\)

Using Pythagoras theorem


\(l^2 + l^2 = 12^2\)

\(2l^2 = 144\)

divide both sides by 2

\(l^2 = 72\)

Therefore, the Area of the square is \(72 cm^2\)