?
3. The given figure looks like a right trapezium.
4. The given figure looks like a isosceles
trapezium. If so, then
3. Draw DE _|_ AB
Thus, MN=17+(21-17)/2=19.
4. Draw AE, DF _|_ BC
Thus MN=64+(82-64)/2=73.
Krishnamurthy
The length of the midsegment of trapezoid is
half the sum of the lengths of the two parallel sides.
3.
Midsegment = 19
4.
Midsegment = 73
la console
First picture
2b.sin(β) = 21 - 17
2b.sin(β) = 4
b.sin(β) = 2
sin(β) = 2/b
ℓ = red + bleu
ℓ = 17 + b.sin(β) → we've just seen that: sin(β) = 2/b
ℓ = 17 + b.(2/b)
ℓ = 17 + 2
ℓ = 19
Second picture
white = 2a.sin(α) + 2b.sin(β) → you know that: white = 82 - 64
2a.sin(α) + 2b.sin(β) = 82 - 64
2a.sin(α) + 2b.sin(β) = 18
a.sin(α) + b.sin(β) = 9
a.sin(α) = 9 - b.sin(β)
ℓ = cyan + red + blue
ℓ = b.sin(β) + 64 + a.sin(α) → we've just seen that: a.sin(α) = 9 - b.sin(β)
ℓ = b.sin(β) + 64 + 9 - b.sin(β)
ℓ = 64 + 9
ℓ = 73
The Gnostic
It's half the sum of the lengths of the parallel sides. 19 and 73 respectively.
Anonymous
It's the average of the parallel sides.
Q1. (21+17)/2 = 19
Q2. (64+82)/2 = 73