Answer:
Identity is verified.
Step-by-step explanation:
We have to verify the identity 
To prove any identity we always prove one side(either left hand side or right hand side) of the equation equal to the other side.
In this identity we take the left hand side first
(as we know cos(a+b) = cosa×cosb-sina×sinb)
= - sinx ( Right hand side)
Hence identity is proved.
Answer:
(C) 18cm, 39cm, 21cm and 45cm.
Step-by-step explanation:
The quadrilateral HIJK has sides measuring 12 cm, 26 cm, 14 cm, and 30 cm.
When HIJK is dilated with a scale factor of 1.5, the side lengths becomes:
12 X 1.5 =18 cm
26 X 1.5 =39 cm
14 X 1.5 =21 cm
30 X 1.5 =45 cm
A dilation of HIJK with a scale factor of 1.5 will give us the side lengths:
18cm, 39cm, 21cm and 45cm.
<u>The correct option is C.</u>
Answer:
Shortest side = 39 cm.
Median side = 65 cm.
Longest side = 91 cm.
Step-by-step explanation:
The perimeter in total is 195 cm. The ratio of the sides are 3 : 5 : 7.
First, find how much parts there are as a whole, by combining the ratios:
3 + 5 + 7 = 15 parts.
Divide the total of parts from the total measurement:
195/15 = 13
Each part has the measurement of 13 cm.
1 part = 13 cm.
Use the following ratio to solve for each of the sides:
Shortest side: 3
3 x 13 = 39
Shortest side = 39 cm.
Median side: 5
5 x 13 = 65
Median side = 65 cm.
Longest side: 7
7 x 13 = 91
Longest side = 91 cm.
Check. Combine all side measurements together. They should equal 195:
39 + 65 + 91 = 195
(39 + 65) + 91 = 195
(104) + 91 = 195
195 = 195 (True).
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