Term 1 review
Answers are for parents and teachers.
1
In a class of 40 pupils the favourite fruits are mango 14, orange 10, banana 8 and strawberry 8. Find the central angle of each sector of a pie chart and check the total.
Angle = number ÷ 40 × 360°: mango 126°, orange 90°, banana 72°, strawberry 72°. Total: 126 + 90 + 72 + 72 = 360°.
2
Find the midpoint of P(−5, 2) and Q(3, −6), and the lengths of the projections of PQ on the two axes.
Midpoint ((−5 + 3) ÷ 2, (2 − 6) ÷ 2) = (−1, −2). On the x-axis |3 − (−5)| = 8 and on the y-axis |−6 − 2| = 8.
3
The angles of a triangle are x, 2x and (3x + 30)°. Find them.
6x + 30 = 180, so x = 25. The angles are 25°, 50° and 105°.
4
The angles of a polygon add up to 2340°. How many sides does it have?
2340 ÷ 180 = 13, so n − 2 = 13 and n = 15.
5
A shop raises a price of 800 LE by 10% and later lowers the new price by 10%. Is the final price 800 LE? Explain.
After the rise: 800 × 110 ÷ 100 = 880 LE. After the fall: 880 × 90 ÷ 100 = 792 LE. No: the second 10% is of a bigger number, so the final price is 8 LE less.