7a-2b = 5a + b
2a=3b
a = 3b/2
Answer:
Number one is 54
Step-by-step explanation:
Step-by-step explanation:
> find the angle of center circle:
cos~¹ 5/(5+12) = cos~¹ 5/17 = 72°
so the sector area of the shaded
region =
(360-72)/360 × 3.14 × 5²
= 288/360 × 78.5
= 62.8
> the height of triangle (red Line) =
4×tan 72° = 4× 3.078 = 12.31
the height of pyramid (green
Line) = √12.31²-8.5² =√74.16
= 8.61
so the volume of pyramid =
⅓×(17×8)×8.61 = 390.32
Option B:

Solution:
In the given figure
.
If two triangles are similar, then their corresponding sides and angles are equal.
By CPCTC, in
,
– – – – (1)
– – – – (2)
– – – – (3)
– – – – (4)
– – – – (5)
– – – – (6)
Option A: 
By CPCTC proved in equation (2)
.
Therefore
. Option A is false.
Option B: 
By CPCTC proved in equation (1)
.
Therefore Option B is true.
Option C: 
By CPCTC proved in equation (4)
.
Therefore
. Option C is false.
Option D: 
By CPCTC proved in equation (5)
.
Therefore
. Option D is false.
Hence Option B is the correct answer.

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