Trigonometry:
We know that csc x = 1 / sin x and π = 180°;
sin 5π/ 6 = sin 150° = 1/2
csc 2π / 3 = 1 / sin 120° = 1 / √3/2 = 2 / √3
Finally:
4 · 1/2 + 7 · ( 2 / √3 )² = 2 + 7 · 4/3 =
= 2 + 28/3 = 2 + 9 1/3 = 11 1/3
Y +6 =(1/2)(x+4)
y +6 = 1/2 x +2
y=1/2 x - 4
or 1/2 x -y = 4
Answer:
1. 3/2
2. 25/16
3. x^2
Step-by-step explanation:
1.
= 
1 x (3/2)
Just measure the width (or height, if you'll be stacking the pennies
a mile high) of a penny, then divide 5280 feet by whatever you find.
This is a great activity for a class, and in fact a good way to start
the project. First take one penny, and work out an answer. Then get
100 pennies, and measure them; do the same calculation to see how many
pennies it will take to make a mile. There will probably be a
difference, because you can measure 100 pennies more accurately than a
single penny. Or maybe you have a micrometer that will measure one
penny precisely. Which is better can be a good discussion starter. And
don't forget to try it in metric, too.
Just to illustrate, using a very rough estimate of a penny's width,
let's say a penny is about 3/4 inch wide. The number of pennies in a
mile will be
5280 ft 12 in 1 penny
1 mile * ------- * ----- * ------- = 5280 * 12 * 4/3 pennies
1 mi 1 ft 3/4 in
This gives about 84,480 pennies. (This method of doing calculations
with units is very helpful, and would be worth teaching.)
If we measure 100 pennies as 6 ft 1 in, we will get
5280 ft 100 pennies
1 mile * ------- * ----------- = 5280 * 100 * 12 / 73 pennies
1 mi 6 1/12 ft
This gives us 86794.5205 pennies in a mile.
Assuming they are dice, to work out the probability that the product is 8, the dice either have to be 2 and 4 or 4 and 2. The blue dice therefore has to be a 2 (4 is not less than 3), which is a 1 in 6 probability. The yellow one therefore has to be 4, which again is 1 in 6. The probablility that these both happen at the same time is given when they are multiplied together.
x
=
.
Hope that is useful.
