z.1
h = y + x = 0,5 a + 0,5 b = 4√2 + 3√2 = 7 √2
P = h2 = 49*2 = 98 [j2]
c2 = x2 + y2 = 32 + 18 = 50 = 25*2
c = 5√2
Obwód
L = a + b +2 c = 8√2 + 6√2 + 10√2 = 24√2
====================================
II sposób pole
P =√2 x* √2y + x2 + y2 = 2*3√2*4√2 + 18 + 32 =
= 48 + 50 = 98
Wszystko przeliczone na literkach, wstawiaj, licz, myśl
x2 + x2 = a2
2x2 = a2
| a2 | ||
x2 = | ||
| 2 |
| a | ||
x = | ||
| √2 |
| b | ||
y = | ||
| √2 |
| a − b | ||
w = | ||
| 2 |
| a − b | a + b | |||
r = a − w = a − | = | |||
| 2 | 2 |
| a + b | a + b | |||
h2 + ( | )2 = ( | )2 | ||
| 2 | √2 |
| (a + b)2 | (a + b)2 | |||
h2 = | − | |||
| 2 | 4 |
| (a + b)2 | ||
h2 = | ||
| 4 |
| a + b | ||
h = | ||
| 2 |
| a + b | a + b | |||
P = | * h = ( | )2 | ||
| 2 | 2 |
| a + b | a − b | |||
( | )2 + ( | )2 = c2 | ||
| 2 | 2 |
| a2 + b2 | |
= c2 | |
| 2 |
| √a2 + b2 | ||
c = | = U{√2a2 +2b2{2} | |
| √2 |
c2 = (√2 x)2 + (√2y)2 = 2 x2 + 2y2 = 2*18 + 2*32 = 36 + 64 = 100
c = 10
L = a + b + 2 c = 8√2 + 6√2 + 20 = 20 + 14 √2
=====================================
L(ABCD)= 20+14√2 [j]