Exercise 1. 1

1.x^2=6^2+8^2

x= 100

x= 10

2.y^2= 13^2-5^2

y= 144，

y= 12。

2, solution, according to Pythagorean theorem: BC? =AB？ -AC? = 17? - 15? =64, so BC=8,

So s △ ABC =/kloc-0 /×15× 8 = 60cm2,

3. The sum of the areas of two larger squares is equal to the area of the largest square, and the sum of the areas of two smaller squares is equal to the area of the largest square.

4. Let CD⊥AB be behind point D and point C,

∵CA=CB=5cm，AB=6㎝，

∴AD=3 cm,

∴CD=√AC？ -Advertising? =√5? -3? =4 cm,

So s △ ABC =1ab× CD = 2 =1× 6× 4 =12cm2.

I hope I can solve your problem.