✔ 最佳答案
1)Take Pie equals 22 over 7.Find the area of:
a)a square with perimeter 60 cm
side of square = 60 cm/4 = 15 cm
Area of square = l side x length = 15 cm x 15 cm = 225 cm^2
b)a triangle with base 5 cm and height 6 cm
area of triangle = base x height / 2 = 5 cm x 6 cm /2 = 15 cm^2
c)a square with side 13mm
Area of square = length of side x length of side = 13 mm x 13 mm = 169 mm^2
d)a rectangle with side 15cm and perimeter 50 cm
length of rectangle = (perimeter – 2x width )/2 = 50 cm – 2 x 15 cm)/2 = 10 cm
area of rectangle = width x length = 15 cm x 10 cm = 150 cm^2
e)a trapezium with upper base 3cm, lower base 2cm and height 8cm
area of trapezium = (upper base + lower base) x height /2
= (3 + 2) x 8 cm/2 = 20 cm^2
f)a right-angled triangle with sides 6 cm, 8cm and 10cm
The hypotenuse of the triangle = 10 cm
Area of triangle = base x height /2 = 6 cm x 8 cm /2 = 24 cm^2
(Pythagorean theorem, 6^2 + 8 cm^2 = 10 cm^2)
The side 6 cm is perpendicular to side 8 cm
The hypotenuse does not come into calculation of area of triangle in this case)
Of course, one can use Heron formula to calculate area of triangle if the length of 3 sides are known for any type of triangle.
2)
Volume of a cube = length of side^3
Length of side = cubic root of volume = cubic root of 5832 cm^3 = 18 cm
3)
Volume of water a giant drinks = (2500 m^3) /2 = 1250 m^3
Volume of water = length x width x depth = 50 cm x 25 cm x depth
1250 m^3 = 50 m x 25 m x depth
depth = 1250 m^3 /(50 m x 25 m) = 1 m
4)
time = distance /speed
time required to travel from City A to City B = 120 km/40 km/h = 3h
time required to travel from City B to City A = 120 km/60 km/h = 2h
All together, the two journeys require = 3h + 2 h = 5 hours
Comment:
PIE means pi = 22/7 = 3.14159…. a constant in maths..
2010-08-10 06:29:57 補充：
回答者：涼
問題 (1) 完全不需要圖,你是否誤解 PIE 這字
所以希望有圖. 這個字 PIE = PI = 22/7 = 3.14159
