Đáp án:
$\widehat{N}=58^o$
$MN ≈ 18,58$ cm
$NP ≈ 22,16$ cm
Giải thích các bước giải:
$\widehat{N}=180^o-70^o-52^o=58^o$
Kẻ $MH⊥NP$, xét $ΔMHP$ vuông có:
$MH=MP.\text{sin}P$
$=20.\text{sin}52^o$
$≈ 15,76$ (cm)
$HP=MP.\text{cos}P$
$=20.\text{cos}52^o$
$≈ 12,31$ (cm)
Xét $ΔMHN$ vuông có:
$NH=MH.\text{cot}N$
$=15,76.\text{cot}58^o$
$≈ 9,85$ (cm)
$→ NP=NH+HP=9,85+12,31 ≈ 22,16$ (cm)
$MN=\dfrac{MH}{\text{sin}58^o}$
$≈ 18,58$ (cm)
