9.B Реши задачи:

isosceles triangle равнобедренный треу­гольник

rectangular triangle (right- angled triangle) прямоу­гольный треугольник

base основание

side сторона

equilateral triangle равносто­ронний треугольник

altitude высота

radius (мн. radii, radiuses) радиус

parallelogram параллелограмм

circle круг

1. Find the area of an isosceles triangle if its base is 4 cm and its altitude is 5 cm (centimeters).

2. Find the area of an equilateral triangle if its base is 6 cm and its altitude is 5 cm.

3. Find the area of a rectangular triangle if its base is 4 cm and its altitude is 5 cm.

4. Find the area of a square if its side is 4 cm.

5. Find the area of a parallelogram if its base is 8 cm and its altitude is 5 cm.

6. Find the area of a circle if its radius is 10 cm.

Как читаются математические действия:

(x) — multiply, times (:) — divide, divided by (+) — add, sum up, plus (-) — subtract, minus (=) — equals, is equal, makes 2² — two in the second power

addition сложение 12 + 15 = 27 Twelve plus fifteen is (makes, equals) twenty seven.

addend слагаемое

sum сумма

subtraction вычитание 41 — 24 = 17 Forty-one minus twenty-four is (equals) seventeen.

minuend уменьшаемое

subtrahend вычитаемое

remainder, difference разность

to do subtraction вычитать

multiplication умножение 6 x 4 = 28 Seven times four is twenty-eight (seven multiplied by four is twenty-eight) multiplicand множимое

multiplier (factor) множитель

product произведение

multiplication table таблица умножения

division деление 60 : 10 = 6 Sixty divided by ten is six.

dividend делимое

divisor делитель

quotient частное

division with remainder деление с остатком

without remainder без остатка

9.C Пропиши словами и реши:

1. -7 + 9 =

2. 0,02 x 1,8 =

3. ½ + ³/₈ =

4. 30 x 0,55 =

5. -12 : 6 =

6. 32 : 0,11x – 4 = 17

7. 20x + ¹/₄ – 8 = 12x

8. 2² – x = 8³

9. 102x + 16 = 85x : 3

10. 17 + 3²/₅ -10x = 52

9.D Реши задачи:

1. Convert 5/12 to a decimal.

2. Express 0,28 as a fraction.

3. What is 67.469 to 3 significant figures.

4. Find 16% of 8.

9.E Реши задачи:

percentage процент; dealer торговец; mark-up наценка.

1. Find 21 as a percentage of 193.

2. The price of an item including the dealer’s 15% mark-up is $28. What did it cost before the mark-up?

3. If it costs 8$ to drive x kilometres, then what is the cost of driving 2 kilometres?

9.F Реши задачи:

1. Faceplates priced at x pence per dozen are repacked in boxes of 100. What will the cost of such a box be, in pounds?

2. There are x female workers and y male workers in a factory. Write down an algebraic expression to show that the total work force must be less than 150.

3. Where does the graph of s = 3t + 5 cross the x-axis?

MODULE 10

STRUCTURAL ENGINEERING AND INTERESTING CONSTRUCTIONS