Answer:
number = 267
Step-by-step explanation:
i am a 3 digit number divisible by 3.
100a + 10b + c
my tens digit is 3 times as great as my hundreds digit
b = 3a, from this we know a = 1, 2, 3, then b = 3, 6, 9
and the sum of my digits is 15.
a + b + c = 15
if you reverse my digits i am divisible by 6 and 3
100c + 10b + a
this is a logic problem, an equation won't help us here
From the given information b = 3a, and the sum of the 3 digits = 15, we have:
1 3 ___; three single digits can't add up to 15
2 6 _7_; this has to be the number
3 9 _3_; reverse number is not different
Check for division by 3 and 6
267/3 = 89
762/6 = 127
267 is the number
From right triangle trigonometry, we have the following:

,
where the "opposite side" means the opposite side to angle with measure

, and "adjacent side" means the adjacent side to angle with measure

.

is a constant which can be found using a calculator.
In the calculator of the pc press: view - scientific - 35 - tan.
This gives

Thus, back in the equation

we substitute as follows and solve:


Answer: 8.4 cm
Answers:
- The lengths of sides PQ and RS are <u> 13 </u>
- The lengths of sides QR and SP are <u> </u><u>20 </u>
This is a 13 by 20 rectangle.
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Explanation:
Refer to the drawing below.
Let x be the length of side SP. Since we're dealing with a rectangle, the opposite side is the same length. Side QR is also x units long.
We're told that RS = SP - 7 which is the same as saying RS = x-7
We also know that PQ = x-7 as well because PQ is opposite side RS.
In short, we have these four sides in terms of x
- PQ = x-7
- QR = x
- RS = x-7
- SP = x
as shown in the drawing. The four sides add up to the perimeter of 66.
PQ+QR+RS+SP = perimeter
PQ+QR+RS+SP = 66
(x-7)+x+(x-7)+x = 66
4x-14 = 66
4x = 66+14
4x = 80
x = 80/4
x = 20
Use this x value to find the unknown side lengths.
- PQ = x-7 = 20-7 = 13
- QR = x = 20
- RS = x-7 = 20-7 = 13
- SP = x = 20
In short, this is a 13 by 20 rectangle.
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Check:
perimeter = side1+side2+side3+side4
perimeter = PQ+QR+RS+SP
perimeter = 13+20+13+20
perimeter = 33+33
perimeter = 66
The answer is confirmed.
Everyone works differently in mental meth.
To calculate 9*52, we note that 9=10-1, so mentally calculate
9(52)
=(10-1)(52)
=520-52 [ subtract 20 from each number]
=(520-20)-(52-20)
=500-32
=468.
Alternatively,
9*52=9*50+9*2=450+18=468
If you're good with multiplication and division,
9*52=3*3(52)=3*156=450+18=468