We can find h by calculating the area S of the parallelogram in two ways. We can write:

. On the other hand,

. Then:
Let the required number is 2x ,
According to the condition,
➡ 10 times the sum of half of 2x and 6 = 8

Therefore the value of x is -5.2
And, required number is -5.2
Answer: y = 90°
Step-by-step explanation:
55.30786941 = sin-1 (148/180) round to 55.3° angle x
34.69213059 = cos-1 (148/180) . round to 34.7° "angle z" at right
34.7 +55.3 = 90
Sum of All angles of the triangle = 180° 180 -90 = 90
If angle x is 55.7 and angle z is 34.7° Angle y must be 90°
Ratio of inscribed arcs = ratio of chord to diameter