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Misha Larkins [42]
3 years ago
8

Show cos 20 * cos 40 * cos 80 =1/8

Mathematics
1 answer:
Delicious77 [7]3 years ago
8 0
 cos 20 cos 40 cos 80 = 
= ( 2 sin 20 cos 20 cos 40 cos 80 ) / 2 sin 20 =
( multiple and divide by 2 sin 20 )
= ( sin 40 cos 40 cos 80 ) / 2 sin 20 =
= ( 1/2 sin 80 cos 80 ) / 2 sin 20 = 
= ( sin 80 cos 80 ) / 4 sin 20 = 
= 1/2 sin 160 / 4 sin 20 = 
= sin 160 / 8 sin 20 =  ( and since:  sin 160 = sin 20 )
= 1 / 8 
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I would search it on google tbh
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4 years ago
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Trapezoid QRST has two right angles. A 5in. altitude can be drawn dividing QRST into a rectangle and an isosceles right triangle
iVinArrow [24]
The area of the trapezoid is 57.5 square inches.

If you draw out the description, you will see that your trapezoid can be divided into a rectangle that is 9 x 5 and an isosceles right triangle with a base of 5 and height of 5. 

Just find the areas of both and add them together.

Rectangle:
5 x 9 = 45

Triangle:
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45 + 12.5 = 57.5
5 0
3 years ago
Who walks the faster rate: someone who walks 60 feet in 10 seconds or someone who takes 5 seconds to walk 25 feet?
True [87]
To determine the rate that an individual walks. Take each set values and put in the following formula to solve for the rate.

Rate = number of feet/ seconds

Person 1 = 60 feet / 10 seconds = 6 feet/sec

Person 2 = 25 feet / 5 seconds = 5 feet/second

Person 1 walks at a faster rate than person 2.
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4 years ago
The number 1.255 is an example of a decimal number
vodomira [7]

Answer: The statement is - True.

Step-by-step explanation:

The decimal numbers are numbers that have a decimal point in them. In this case, 1.255, we have a decimal point between the number 1 and the rest of the numbers. The number 1 is an ordinary full number, while the 0.255 is part of a number, thus the decimal.

The numbers in the decimal all have their own specific meaning. The first number is part of the tenths, in this case that is the number 2. The second number is part of the hundreds, in this case it is the number 5. The second number is part of the thousands, in this it is the last number, also number 5.

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4 years ago
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The lengths of 10 ribbons are 100 cm, 110 cm, 95 cm, 60 cm, 20 cm, 60 cm, 110 cm,
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The modal lengths of the ribbons are 60 cm and 110cm.

If the length 110 is removed, the new model length would be 60 cm.

<h3>What is the mode?</h3>

Mode refers to a value that appears most frequently in a data set. Mode is a measure of central tendency. 110 and 60cm occur twice in the dataset. Thus, they are the mode lengths.

To learn more about mode, please check: brainly.com/question/16505756

#SPJ1

4 0
2 years ago
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